American and British spelling: the patterns behind color and colour
Most differences between American and British spelling are not a long list of exceptions but a few regular patterns. Learn the patterns, pick one variety, and apply it consistently.
Where the split came from
Until the eighteenth century English spelling varied a great deal on both sides of the Atlantic. Samuel Johnson's A Dictionary of the English Language (1755) did much to settle British usage, generally preferring spellings that reflected French or Latin origins, such as colour and centre. In the United States, Noah Webster championed simpler, more phonetic forms, first in his popular spelling book of the 1780s and then in An American Dictionary of the English Language (1828). Many of the spellings he promoted, such as color, center and defense, became American standard; some of his more radical proposals never caught on. Merriam-Webster, which descends from Webster's dictionary business, has a short account on its site, and the Wikipedia overview of spelling differences lists hundreds of examples.
Canada, Australia, New Zealand, Ireland, India and South Africa each have their own conventions, mostly close to British spelling with some American features; Canadian English, for example, generally uses colour but tire rather than tyre. This article sticks to the American/British contrast, which is what the two word lists in the spell checker cover.
The main patterns
-or / -our
American color, honor, labor, neighbor, favorite; British colour, honour, labour, neighbour, favourite. Note that British English drops the u in some derived forms: humour but humorous, vigour but vigorous. And some words have -or everywhere: doctor, error, mirror.
-er / -re
American center, theater, meter, fiber, liter; British centre, theatre, metre, fibre, litre. British English keeps meter for a measuring device (a gas meter) and metre for the unit. Words such as acre, massacre and mediocre keep -re in American English too, because -cer would suggest a soft c.
-ize / -ise
This is the most misunderstood pattern. American English uses -ize (organize, realize, recognize). British English accepts both: -ise is more common in British newspapers and everyday writing, but -ize is the house style of Oxford University Press and is sometimes called "Oxford spelling". So organize is not automatically an Americanism. The same applies to -ization/-isation. A handful of words take -ise in both varieties because the ending is not the Greek-derived suffix: advertise, advise, compromise, exercise, revise, surprise, televise.
The related -yze/-yse pattern is stricter: American analyze, paralyze, British analyse, paralyse in all styles.
Doubling a final l
When adding a suffix to a word ending in a vowel plus l, British English usually doubles the l regardless of stress (travelled, travelling, traveller, cancelled, modelling), while American English doubles it only when the final syllable is stressed (traveled, traveling, canceled, but compelled in both). Confusingly, the pattern partly reverses for some base words: American enroll, fulfill, skillful, installment, British enrol, fulfil, skilful, instalment.
-ense / -ence
American defense, offense, pretense, license; British defence, offence, pretence. British English also distinguishes noun and verb: a licence (noun) lets you license (verb), just as practice (noun) is what you practise (verb). American English uses license and practice for both.
-og / -ogue
American usage often allows catalog, dialog, while British uses catalogue, dialogue. In American writing catalog is very common and dialogue is still widely preferred outside computing (dialog box).
ae and oe
Words from Greek and Latin often simplify to e in American English: anemia, pediatric, estrogen, maneuver versus British anaemia, paediatric, oestrogen, manoeuvre. Some simplified forms such as encyclopedia and medieval are now common in Britain too.
Individual words
Outside the patterns, a short list of words simply differ:
| American | British | Note |
|---|---|---|
| gray | grey | both are found in each country; these are the usual preferences |
| tire | tyre | for the wheel; tire (to get weary) is the same everywhere |
| curb | kerb | for the pavement edge; curb as "restrain" is shared |
| check | cheque | for the bank document only |
| program | programme | British uses program for computer software |
| aluminum | aluminium | also a difference in pronunciation |
| plow | plough | |
| jewelry | jewellery | |
| mold | mould | |
| pajamas | pyjamas | |
| skeptic | sceptic | |
| judgment | judgement | British legal usage often prefers judgment |
Choosing and staying consistent
Neither variety is more correct. What readers and editors notice is inconsistency: color in one paragraph and colour in the next. Practical guidance:
- Follow your audience or publisher. Many organizations publish a style guide; if yours does not, choose the variety of most of your readers.
- Set your tools to match. Word processors and browsers let you choose the dictionary language; in HTML, the
langattribute (en-US,en-GB) tells the browser which one to use. Our article on the HTML spellcheck attribute explains how. - Do not "correct" quotations or names. The Labour Party keeps its u in an American article, and the World Trade Center keeps -er in a British one.
- Decide on -ize/-ise once for British text, and note it in your style sheet. Both are acceptable; mixing them is not.
To check a document against one variety, paste it into the spell checker with the American or British list selected: words spelled the other way will be flagged, and the suggestion list will usually offer the matching form. Note that the British list follows the more common -ise convention, so if you write in Oxford spelling, add your -ize words to "my words" or expect them to be flagged.