email: email vs e-mail
Once routinely hyphenated, the unhyphenated form is now universal across major English style guides.
Style Guide Spelling Decisions
For each disputed English word, what does each major style guide actually prescribe? We compare the AP Stylebook, Chicago Manual of Style, MLA Handbook, APA Publication Manual, Garner's Modern English Usage, and Merriam-Webster, citing the published editions directly.
website: website vs Web site
AP dropped 'Web site' in 2010, capping a decade-long migration toward the closed compound.
OK: OK vs okay
AP firmly prefers 'OK' (no periods); Chicago and MLA accept both; the spelled-out form is more common in fiction.
adviser: adviser vs advisor
AP prescribes 'adviser'; Chicago accepts both. Merriam-Webster lists 'adviser' as the main form with 'advisor' as a variant.
judgment: judgment vs judgement
American English drops the middle 'e'. Legal contexts strictly use 'judgment' even in British English.
acknowledgment: acknowledgment vs acknowledgement
American style guides drop the medial 'e'; British prefers it. APA section heading is 'Acknowledgments'.
internet: internet vs Internet
AP lowercased 'internet' in 2016; Chicago followed in 2017. The capitalized 'Internet' is now historical.
podcast: podcast vs pod cast
Coined as 'pod-cast' in 2004, the closed-compound form was standardized within two years.
smartphone: smartphone vs smart phone
All major guides treat 'smartphone' as a closed compound; the two-word form is now considered dated.
data: data (singular) vs data (plural)
APA 7 still treats 'data' as plural ('data are'); AP and most journalism use it as a singular mass noun.
percent: percent vs per cent
American guides write 'percent' as one word; British 'per cent' is two. APA 7 uses the % symbol with numerals.
goodbye: goodbye vs good-bye
Once routinely hyphenated through the mid-20th century, 'goodbye' as a closed compound now dominates.
vice versa: vice versa vs vice-versa
Now fully naturalized in English; major guides drop both italics and hyphenation.
cliché: cliché vs cliche
AP drops the accent for typesetting simplicity; Chicago and academic guides retain it.
résumé: résumé vs resume
AP strips accents; academic and Chicago style retain them to disambiguate from the verb 'resume'.
naïve: naïve vs naive
AP drops the diaeresis; Chicago and most academic style retain it to mark the separated vowels.
cooperate: cooperate vs co-operate
All American guides close the compound; British editors sometimes retain 'co-operate' but the closed form is standard.
reelect: reelect vs re-elect
AP retains the hyphen to break the double 'e'; Chicago and Merriam-Webster prefer the closed form.
antivirus: antivirus vs anti-virus
All major guides close the 'anti-' prefix in established compounds; the hyphenated form is now considered dated.
e-book: e-book vs ebook
Most style guides retain the hyphen for 'e-' prefixes (e-book, e-commerce); 'email' is the notable exception.
e-commerce: e-commerce vs ecommerce
Style guides retain the hyphen; brand and tech industry usage often drops it (Shopify, BigCommerce).
health care: health care (n.) / health-care (adj.) vs healthcare
AP keeps the noun open and hyphenates the adjective; Merriam-Webster accepts the closed form 'healthcare', which has become dominant in industry usage…
child care: child care vs childcare
American style guides keep 'child care' open as a noun; British English often closes it to 'childcare'.
homepage: homepage vs home page
Most style guides have closed the compound, though Merriam-Webster still lists it open as the main form.
log in (verb) / login (noun): log in (v.) / login (n.) vs login (verb)
Universal: the verb is two words ('log in to your account'), the noun is one word ('your login').
set up (verb) / setup (noun): set up (v.) / setup (n.) vs setup (verb)
Verb is two words, noun is closed. Confusion with 'setup' as a verb is among the most common style errors in technical writing.
back up (verb) / backup (noun): back up (v.) / backup (n., adj.) vs backup (verb)
Verb is open ('back up your files'); noun and adjective are closed ('a backup copy').
log out (verb) / logout (noun): log out (v.) / logout (n.) vs logout (verb)
Same pattern as 'log in / login': verb open, noun closed. Often confused in UI button copy.
everyday (adj.) / every day (adv.): everyday (adj.) / every day (adv.) vs everyday (adverb)
Adjective ('everyday low prices') is one word; adverbial ('I run every day') is two. The single most common style-guide distinction.
anymore: anymore vs any more
American style closes 'anymore' as an adverb of time; British English often keeps 'any more' open.
all right: all right vs alright
Major style guides reject 'alright'; Garner's calls it 'still considered nonstandard'. Merriam-Webster marks it as a variant.
awhile (adv.) / a while (n.): awhile (adv.) / a while (n.) vs awhile (after preposition)
After a preposition use 'a while' ('for a while'); standalone adverb use 'awhile' ('stay awhile'). Garner's calls this 'one of the trickiest style poi…
into / in to: into (preposition) / in to (adverb + preposition) vs into (always)
'Into' shows direction or transformation; 'in to' is the adverb 'in' followed by the preposition 'to' ('she turned in to the police').
onto / on to: onto (preposition) / on to (adverb + preposition) vs onto (always)
'Onto' indicates physical motion to a surface; 'on to' is the adverb followed by 'to' ('move on to the next topic'). Chicago Manual provides the canon…
toward: toward vs towards
American guides drop the 's'; British 'towards' is standard in the UK and Commonwealth English.
afterward: afterward vs afterwards
Same pattern as 'toward': American style drops the 's'; British retains it.
gray: gray vs grey
American 'gray', British 'grey'. Both spellings appear in proper nouns (Earl Grey tea, Dorian Gray) regardless of dialect.
theater: theater vs theatre
American 'theater'; British 'theatre'. Many American venues retain 'theatre' in their proper names.
dialogue: dialogue vs dialog
Most American style guides keep the '-ue' ending; 'dialog' survives mainly in computing ('dialog box').
catalog: catalog vs catalogue
American style drops the '-ue'; British retains it. Library and museum proper names often keep 'catalogue'.
traveling: traveling vs travelling
American spelling uses one 'l' on '-ing' and '-ed' forms of multisyllable verbs ending in 'l'; British doubles it.
canceled: canceled vs cancelled
Same pattern as traveling/travelling: American single 'l', British double 'l' on inflected forms.
fulfill: fulfill vs fulfil
American 'fulfill' (double l); British 'fulfil' (single l). Inflected forms double in both: fulfilled, fulfilling.
skillful: skillful vs skilful
American 'skillful'; British 'skilful'. Same pattern applies to willful/wilful and instillful/instilful.
color: color vs colour
Canonical -or/-our split. Same pattern: favor/favour, honor/honour, labor/labour, neighbor/neighbour.
organize: organize vs organise
American -ize, British often -ise. Oxford English Dictionary actually prefers -ize even in British English.
analyze: analyze vs analyse
American 'analyze'; British 'analyse'. Unlike -ize/-ise, here Oxford does NOT prefer -yze for British English.
esophagus: esophagus vs oesophagus
American medical writing drops the leading 'o-'; British retains it. Same pattern as estrogen/oestrogen, fetal/foetal.
fetal: fetal vs foetal
AMA Style Manual prescribes 'fetal' for all medical literature; British medical journals retain 'foetal'.
anemia: anemia vs anaemia
American style drops the 'a' from 'ae' digraphs in medical terms; British retains them: anemia/anaemia, leukemia/leukaemia, pediatric/paediatric.