They are two spellings of the same word, split by dialect: <strong>grey</strong> is standard in Britain, Ireland, Australia and New Zealand ("a grey November sky"), while <strong>gray</strong> is standard in the United States ("his hair turned gray"). The pronunciation and meaning are identical — only the vowel letter changes.
The core difference
There is no difference in shade, formality or part of speech. British writers use grey for the colour, the verb ("his hair is greying") and the compounds ("grey area", "grey matter", "greyish"). American writers use gray throughout in exactly the same slots. Canadian writing accepts both but leans towards grey.
The test
Look at the vowel and match it to the country: grEy for England, grAy for America. That mnemonic is the whole rule, and it survives every ordinary use of the word.
Where the spelling is fixed regardless of dialect
A handful of words keep their spelling on both sides of the Atlantic, because the spelling is part of a name or a fixed term:
- Greyhound — the dog and the American bus company are both spelled with an e.
- Earl Grey — the tea takes an e, always, because it comes from the surname.
- Surnames — a person called Gray stays Gray, and a person called Grey stays Grey. Never "correct" someone's name to your house style.
- The gray (Gy) — the SI unit of absorbed radiation dose is spelled gray in every country, including the UK.
Consistency matters more than the choice
The only genuine error here is mixing the two. A page that offers a "grey colour palette" in the heading and "dark gray" in the caption looks unedited. Set the spelling with your document's dialect, then check the compounds — greyhound aside, they all follow whichever base form you picked: greyscale/grayscale, grey-haired/gray-haired, greyish/grayish.
Design and technical contexts
If you write about code, design or imaging, watch for a clash between prose and syntax. CSS accepts both gray and grey as colour keywords, but many libraries, tokens and file names use the American spelling only. It is normal and correct to write British prose around an American identifier: "set the grey tone using the gray-600 token". Do not change the code to match the prose.
Is one older or more correct?
No. Both spellings have long histories in English, and neither is a modern invention or a corruption of the other. Anyone telling you gray is a mistake means it is unexpected for British readers, which is a matter of audience rather than accuracy.
One last note on greyhound: the breed name has nothing to do with the colour, and the dogs come in many shades. Spell it with an e in a British text and an American one alike.
Frequently Asked Questions
Is it "grey area" or "gray area"?
Both are right; follow your dialect. British and Australian writing uses "grey area", American writing uses "gray area". The meaning — a situation the rules do not clearly cover — is the same.
Which spelling should I use for greyhound?
Greyhound, with an e, in every dialect. It is a fixed form and is not affected by the gray/grey split, even in American English.
Is greyscale or grayscale correct?
Match your base spelling: greyscale in British English, grayscale in American English. In software and image formats, grayscale is far more common as a technical term, so keep it as written in code and file names.