American English differs vastly from British English in spelling, pronunciation, usage and punctuation.  The idea originated with a view to develop a national language with its very own identity.   The Americans have simplified spellings by dropping or interchanging some letters, yet the dictates of phonetics are still dominant.

For instance words ending in “our” in British English becomes “or” in the American form.  Example:  Colour – Color, Labour – Labor.

Similar patterns are seen in the following:
“ise” becomes “ize” standardise/standardize
“tre” becomes “ter” centre/center
“ae”  becomes “e”  encyclopaedia/encyclopedia
“ce”  becomes “se” licence/license

As some clarification is necessary on these issues, we have included a list of common words which highlight the differences between British and American English.  The extensive list comprises different groups of words dealing with American spelling as compared to Greek, Latin and French spelling. It also includes other miscellaneous information providing a proper perspective of the subject.


American                                                        British


amoeba, ameba                                                amoeba
diarrhea                                                            diarrhoea
edema                                                              oedema
enology, oenology                                             oenology
esophagus (oesophagus)                                   oesophagus
estrogen (oestrogen)                                         oestrogen
estrus (oestrus)                                                 oestrus
fetal (foetal)                                                      foetal
fetid, foetid                                                       fetid, foetid
fetor, foetor                                                      fetor
fetus (foetus)                                                     foetus
gonorrhea                                                                     gonorrhoea
homeopath                                                       homoeopath
homeostasis                                                      homoeostasis
maneuver                                                          manoeuvre
menorrhea                                                        menorrhoea
penology                                                                      penology poenology?)

aeon, eon                                                                     aeon, eon
aesthete, esthete                                               aesthete
aesthetic, esthetic                                              aesthetic
anemia                                                              anaemia
anemic                                                              anaemic
anesthetic, ‑thesia, ‑thetist                                 anaesthetic, ‑thesia, ‑thetist
archaeology, archeology                                   archaeology
cesarean (caesarean), cesarian (caesarian)      caesarean, caesarian
cesium                                                              caesium
diaeresis, dieresis                                              diaeresis
encyclopedia, encyclopaedia                             encyclopedia, encyclopaedia
ether                                                                 ether (aether)
fecal (faecal)                                                     faecal
feces (faeces)                                                   faeces
gynecology                                                       gynaecology
hemoglobin                                                       haemoglobin
hemophilia                                                        haemophilia
hemorrhage                                                      haemorrhage
hemorrhoid                                                       haemorrhoid
leukemia                                                           leukaemia
medieval, mediaeval                                          medieval, mediaeval
orthopedics, orthopaedics                                 orthopaedics
paean (pean)                                                    paean
paleobotany                                                      palaeobotany
Paleocene                                                                     Palaeocene
paleoclimatology                                               palaeoclimatology
paleogeography                                                palaeogeography
paleography                                                      palaeography
paleolithic                                                         palaeolithic
paleomagnetism                                                palaeomagnetism
paleontology                                                     palaeontology
Paleozoic                                                          Palaeozoic
pedagogy                                                         paedagogy
pederast                                                           pederast, paederast
pediatrician                                                       paediatrician
pediatric                                                           paediatric
pediatrics                                                          paediatrics
pedophile                                                                     paedophile
pedophilia                                                         paedophilia
primeval                                                           primeval (primaeval)
syneresis, synaeresis                                         synaeresis
synesthesia, synaesthesia                                   synaesthesia

eurythmy, eurhythmy                                         eurhythmy
silent ‑ph‑

apothegm                                                         apophthegm



bisulfate                                                            bisulphate
disulfide                                                            disulphide
sulfate                                                               sulphate
sulfide                                                               sulphide
sulfur, sulphur                                       sulphur
trisulfate                                                            trisulphate



burned, burnt                                                    burnt, burned
dreamed, dreamt                                              dreamt, dreamed
knelt, kneeled                                                   knelt (kneeled)
leaned                                                              leaned, leant
leaped, leapt                                                     leaped, leapt
learned                                                             learned, learnt
smelled, smelt                                                   smelt, smelled
spelled                                                              spelt, spelled
spilled, spilt                                                       spilt, spilled
spoiled, spoilt                                                   spoilt, spoiled
‑f‑/‑gh‑ and ‑ow/‑ough

draft, ‑fty                                                          draught, ‑ghty (only air current, drawing of                    liquid)
draftsman                                                         draughtsman, draftsman (one who makes drawings)
plow (plough), ‑man, ‑share                              plough, ‑man, ‑share
snowplow                                                         snowplough

gypsy, gipsy                                                      gypsy, gipsy
jibe (gybe)                                                        gybe (nautical)
siphon, syphon                                                  siphon (syphon)
tire                                                                   tyre (on vehicles only)
tyke, tike                                                          tyke (tike)
tyro                                                                  tiro (tyro)


amid, amidst                                                     amid, amidst
among, amongst                                                among, amongst
while                                                                while, whilst



accoutre, accouter                                            accoutre
accouterment, accoutrement                              accoutrement
amphitheater                                                     amphitheatre
caliber, calibre                                                  calibre
center                                                               centre
centerboard                                                      centreboard
centerfold                                                         centrefold
centering                                                           centring, centreing
fiber, fibre                                                         fibre
fiberboard, fibreboard                                       fibreboard
fiberglass, fibreglass                                          fibreglass
goiter                                                                goitre
liter (litre)                                                          litre
louver, louvre                                                    louvre, louver
luster, lustre                                                      lustre (brilliance)
maneuver                                                          manoeuvre
meager, meagre                                                meagre
meter                                                                metre (unit of measurement)
miter, mitre                                                       mitre
niter                                                                  nitre
ocher, ochre                                                     ochre
philter, philtre                                                    philtre
reconnoiter, reconnoitre                                    reconnoitre
saber, sabre                                                                  sabre
saltpeter                                                           saltpetre
scepter                                                             sceptre
sepulchre, sepulcher                                          sepulchre
somber, sombre                                                sombre
specter, spectre                                                spectre
theater, theatre                                                  theatre
titer, titre                                                           titre


arbor                                                                arbour
ardor                                                                ardour
armor                                                               armour
armorer                                                            armourer
armory                                                             armoury
behavior                                                           behaviour
behavioral                                                         behavioural
candor                                                              candour
clamor                                                              clamour
clangor                                                             clangour
color                                                                colour (and all derivative words)
demeanor                                                         demeanour
dolor                                                                dolour (literary)
enamor                                                             enamour
endeavor                                                                      endeavour
favor                                                                favour
favorite                                                             favourite
favoritism                                                          favouritism
fervor                                                               fervour
flavor                                                                flavour
glamor, glamour                                                glamour
harbor                                                              harbour
honor                                                               honour
humor                                                               humour
labor                                                                labour
misdemeanor                                                    misdemeanour
neighbor                                                           neighbour
neighborhood                                                   neighbourhood
neighborly                                                         neighbourly
odor                                                                 odour
parlor                                                               parlour
pavior, paviour                                                 pavior or paviour
rancor                                                              rancour
rigor                                                                 rigour
rumor                                                               rumour
savior, saviour                                                  saviour
savor, savour                                                    savour
savory, savoury                                                savoury
splendor                                                           splendour
succor                                                              succour
tumor                                                               tumour
valor                                                                 valour
vapor                                                               vapour
vigor                                                                 vigour


bolt                                                                  bolt (boult) (metal pin)
citrus                                                                citrous (adj)
font                                                                  fount, font
mold, mould                                                     mould (rot)
molding, moulding                                             moulding (ornamental wood or stone)
molt (moult)                                                      moult
smolder, smoulder                                            smoulder

gram                                                                 gram (gramme)
kilogram                                                           kilogram (kilogramme)
program, programme                                        programme (verb)
program                                                                       programme (noun)
program                                                                       program (programme) (computer)
programmed, programed                                  programmed
programmer, programer                                    programmer
programming, programing                                 programming

check                                                               cheque (banking only)
checker                                                            chequer, checker (pattern)

‑og/‑ogue & ‑ege/‑egue

analogue or analog                                            analogue
catalog, catalogue                                             catalogue
dialogue, dialog                                                 dialogue
epilogue, epilog                                                 epilogue
homologue, homolog                                         homologue
monologue, monolog                                         monologue
pedagogue, pedagog                                         pedagogue
prologue, prolog                                               prologue
renege                                                              renege (renegue)
synagogue, synagog                                          synagogue
travelogue, travelog                                           travelogue


connection                                                        connection, connexion
deflection                                                          deflection, deflexion
flexion (flection)                                                flexion
genuflection                                                      genuflection, genuflexion
inflection                                                           inflection, inflexion
reflection                                                          reflection, reflexion
retroflection                                                      retroflexion


advertise                                                           advertise
aggrandize                                                        aggrandize, aggrandise
Americanize                                                      Americanise, Americanize
apologize                                                          apologise, apologize
apprise                                                             apprise (to inform)
apprize                                                             apprize (archaic) (appraise, esteem)
burglarize                                                          burglarise, burglarize
capitalize                                                          capitalise, capitalize
categorize                                                         categorize, categorise
characterize                                                                  characterise, characterize
colonize                                                            colonize, colonise
criticize                                                             criticize, criticise
dramatize                                                          dramatise, dramatize
empathize                                                                     empathize
emphasize                                                         emphasize, emphasise
equalize                                                            equalise, equalize
extemporize                                                      extemporize, extemporise
finalize                                                              finalize, finalise
glamorize, glamourize                                        glamorise, glamorize, glamourise, glamourize
liberalize                                                           liberalize, liberalise
merchandise, merchandize                                 merchandise
mobilize                                                            mobilise, mobilize
motorize                                                           motorise, motorize
naturalize                                                          naturalise, naturalize
normalize                                                          normalize, normalise
organize                                                            organise organize
parameterize or parametrize                              parametrize, parametrise
parenthesize                                                      parenthesize, parenthesise
pasteurized                                                                   pasteurised, pasteurized
popularize                                                         popularise, popularize
realize                                                               realise, realize
recognize                                                          recognise, recognize
romanize                                                           romanise, romanize
satirize                                                              satirise, satirize
stabilize                                                            stabilize, stabilise
standardize                                                                   standardise standardize
surprise, surprize                                               surprise
symbolize                                                                     symbolise, symbolize
tantalize                                                            tantalize, tantalise
vaporize                                                           vaporise, vaporize (not vapourise)

analyze                                                             analyse
catalyze                                                            catalyse
dialyze                                                              dialyse
paralyze                                                            paralyse
balk                                                                  baulk (balk)
cauldron (caldron)                                            cauldron (caldron)
calk (caulk)                                                                  (metal shoe grip)
caulk (calk)                                                                  caulk (goop to stop up boat leaks)
gauge (gage)                                                     gauge

defense                                                             defence
license, licence                                                  license (verb)
license, licence                                                  licence (noun)
offense, offence                                                offence
practice, practise                                              practise, practice (noun)
practice, practise                                              practise (verb)
pretense, pretence                                            pretence
vise                                                                  vice (tool for holding work)



adapter, adaptor                                               adaptor, adapter
adviser, advisor                                                adviser (advisor disputed)
propeller, propellor                                           propeller


employee, employe                                           employee

fagot, faggot                                                                 faggot (bundle of sticks)
fagoting, faggoting                                             faggoting (embroidery)
wagon                                                              wagon, waggon

appall, appal                                                                 appal
distill, distil                                                        distil
enroll, enrol                                                      enrol
enrollment                                                         enrolment
enthrall, enthral                                                 enthral
fulfill, fulfil                                                         fulfil
fulfillment                                                          fulfilment
install, instal                                                      install, instal
installment, instalment                                        instalment
instill, instil                                                        instil
skillful                                                               skilful
thralldom or thraldom                                        thraldom (thralldom)
willful, wilful                                                      wilful

barreled, ‑ling, barelled, ‑lling                            barelled, ‑lling
calisthenics                                                       callisthenics (calisthenics)
caliper                                                              calliper
canceled, ‑ling or cancelled ‑lling                       cancelled, ‑lling
chili, chile, chilli                                                 chilli, chili
councillor or councilor                                       councillor
counseled, ‑ling, counselled, ‑lling                      counselled, ‑lling
counselor, counsellor                                        counsellor
deviled, ‑ling, devilled, ‑lling                              devilled, ‑lling
disheveled, ‑ling or dishevelled, ‑lling                 dishevelled, ‑lling
equaled, ‑ling, equalled, ‑lling                            equalled, ‑lling
fueled, ‑ling, fuelled, ‑lling                                  fuelled, ‑lling
groveled, ‑ling, ‑ler, grovelled, ‑lling, ‑ller     grovelled, ‑lling, ‑ller
hosteler or hosteller                                           hosteller
hosteled, ‑ling or hostelled, ‑lling                       hostelled, ‑lling
jeweler, jeweller                                               jeweller
jewelry                                                             jewellery (jewelry) (note ‑el‑, ‑elle‑)
leveled, ‑ling, levelled, ‑lling                               levelled, ‑lling
leveler, leveller                                      leveller
libeled, ‑ling, libelled, ‑lling                                libelled, ‑lling
libelous, libellous                                               libellous
marvelous or marvellous                                    marvellous
marveled, ‑ling or marvelled, ‑lling                     marvelled, ‑lling
metaled, ‑ling, metalled, ‑lling                            metalled, ‑lling
modeled, ‑ling or modelled ‑lling                       modelled, ‑lling
modeler                                                            modeller
paneled, ‑ling or panelled, ‑lling                         panelled, ‑lling
panelist                                                             panellist
pupilage or pupillage                                         pupillage (pupilage)
quarreled, ‑ling, quarrelled, ‑lling                       quarrelled, ‑lling
quarreler, quarreller                                          quarreller
reveled, ‑ling, revelled, ‑lling                              revelled, ‑lling
scalawag (scallywag)                                        scallywag (scalawag)
traveled, ‑ling, travelled, ‑lling                            travelled, ‑lling
traveler, traveller                                               traveller
troweled, ‑ling, trowelled, ‑lling                         trowelled, ‑lling
woolen or woollen                                            woollen
woolly, wooly                                                   woolly (adj)
woolly, woolie, wooly (pl.‑llies, ‑lies)                woolly (pl. ‑llies) (noun)

kidnapped, kidnaped                                        kidnapped
kidnapper, ‑pping, kidnaper, ‑ping                   kidnapper, ‑pping
worshiped, ‑ping, worshipped, ‑pping               worshipped, ‑pping
worshiper, worshipper                                      worshipper

biased, ‑sing, biassed, ‑ssing                             biased, ‑sing, biassed, ‑ssing      
buses, busses                                                    buses (omnibus)
buses, busses                                                    buses, busses (computer)
focused, ‑sing, focussed, ‑ssing                         focused, ‑sing or focussed, ‑ssing

carburetor                                                                    carburettor
cigarette, cigaret                                               cigarette
clarinetist, clarinettist                                         clarinettist
garrote, ‑ted, ‑ting or garotte, ‑tted, ‑tting          garrotte (garotte)
net                                                                    net (nett) (or money, result, etc)
omelette, omelet                                               omelette, omelet
sulfureted                                                          sulphuretted
dg‑/‑dge‑ (& ‑g‑/‑ge‑)

abridgment, abridgement                                   abridgement (abridgment)
acknowledgment, acknowledgement                 acknowledgement (acknowledgment)
aging, ageing                                                     ageing, aging
fledgling                                                            fledgling, fledgeling
judgment, judgement                                         judgement (judgment)
misjudgment                                                     misjudgement (misjudgment)

encase, incase                                                   encase (incase)
enclose, inclose                                                 enclose (inclose)
endorse, indorse                                               endorse (indorse)
ensure, insure                                                    ensure (make sure)
inquire, enquire                                                 enquire, inquire
inquiry, enquiry                                                 enquiry, inquiry
inure, enure                                                       inure, enure


hyphenation and spaces

antiaircraft                                                        anti‑aircraft
ashtray                                                             ash‑tray, ashtray
bookkeeper                                                      book‑keeper
cooperate                                                                     cooperate, co‑operate
daydream                                                         day‑dream
drypoint                                                            dry‑point
E‑mail                                                              email, e‑mail
flower girl                                                         flower‑girl
flower pot                                                         flower‑pot
lemongrass                                                       lemon grass
neoclassical                                                                  neo‑classical
note paper                                                                    note‑paper
preignition                                                         pre‑ignition
pseudointellectual                                              pseudo‑intellectual
pseudoscience                                                  pseudo‑science
ultrahigh                                                            ultra‑high
ultramodern                                                      ultra‑modern


cafe, cafe                                                          cafe, cafe
elite                                                                  elite
entree, entree                                                    entree
fete, fete                                                           fete
matinee, matinee                                               matinee
naive, naive                                                       naive, naive
role (role)                                                         role, role


B.S.                                                                 B.Sc.
Jr                                                                     Jnr. or Jr.
M.S.                                                                M.Sc.
Sr                                                                     Snr. or Sr.


adze, adz                                                          adze
airplane                                                            aeroplane
aluminum                                                          aluminium
artifact                                                              artefact, artifact
ass (arse)                                                          arse
ax, axe                                                             axe
bail out                                                             bale out, bail out
baloney (boloney)                                             boloney, baloney
battle‑ax                                                           battleaxe
behoove                                                                       behove
boric (boracic)                                                  boracic, boric
cantaloupe, cantaloup                                       cantaloup (cantaloupe)
carcass                                                             carcass, carcase
chamomile (camomile)                                      camomile, chamomile
clerestory, clearstory                                         clerestory
cozy, cosy                                                                    cosy
crayfish, crawfish                                              crayfish (crawfish)
curb                                                                 kerb (edging of road only)
czar, tsar, tzar                                                   tsar, czar
dependent, dependant                                       dependant (noun)
disc, disk                                                          disc (phono record, CD, CD‑ROM, disc harrow)
disk, disc                                                          disk (computing)
disk                                                                  disc (other meanings)
dissension, dissention                                        dissension
doodad                                                                        doodah
doughnut, donut                                                doughnut
flaky (flakey)                                                    flaky
flotation (floatation)                                           flotation, floatation
furor                                                                 furore
gray, grey                                                         grey
jail                                                                    jail, gaol
jailbird                                                              jailbird, gaolbird
jailbreak                                                           jailbreak, gaolbreak
jailer                                                                 jailer, gaoler
karat (carat)                                                                 carat (gold)
ketchup, catsup (catchup)                                 ketchup (catchup)
kumquat                                                                       kumquat (cumquat)
largesse or largess                                             largesse (largess)
lens, lense                                                         lens
licorice                                                             liquorice (licorice)
mollusk or mollusc                                            mollusc
mustache, moustache                                        moustache
naught, nought                                                  nought (digit 0)
night, nite                                                          night
nursling                                                             nursling, nurseling
pajamas                                                            pyjamas
peddler, pedlar                                                 pedlar
persnickety (pernickety)                                    pernickety
pickaninny, picaninny                                        piccaninny
polyethylene                                                     polythene, polyethylene, polyethene
premise, premiss                                               premise, premiss
propellant, propellent                                        propellant (n)
propellant, propellent                                        propellent (adj)
reverie, revery                                                  reverie
Romanian, Rumanian, Roumanian                      Romanian, Rumanian
Romansh, Romansch                                        Romansh, Rumansh
ruble, rouble                                                                 rouble, ruble
sanatorium, sanitarium or sanitorium                  sanatorium
scion (cion)                                                       scion
sissy                                                                 sissy (cissy)
skeptic, ‑al, ‑ism, sceptic, ‑al, ‑ism                  sceptic, ‑al, ‑ism
specialty                                                           speciality
story, storey                                                                 storey (story) (floor of buildings only)
swab (archaic: swob)                                        swab, swob
swap                                                                swap, swop
though, tho                                                                   though, tho'
through, thru                                                     through
tidbit, titbit                                                        titbit
today (to‑day)                                                  today
tonight, tonite                                                    tonight
vial, phial                                                          phial, vial
whiskey, whisky                                               whisky (generic name)
whiskey                                                            whiskey (Irish & American kinds)
whiskeys, whiskies                                            whiskeys, whiskies
whisky                                                              whisky (Scottish kinds)