Grey and gray are both accepted in the English language. They refer to a color of a neutral tone between black and white, and can also be used metaphorically to convey gloom and dullness. However, gray is the more popular spelling in the US, while grey reigns supreme in the UK as well as Ireland, Australia, and other places that use British English. For centuries, the one letter difference between gray and grey has left people wondering if the two have different meanings.
Both spellings evolved from the Old English term grǣg and have retained their primary definition as a color, but many people have sought to assign gray and grey to slightly different shades. For instance, in his work Chromatography; or, a Treatise on Colours and Pigments, and of their Powers in Painting published in 1835, the chemist George Field wrote that gray “denotes a class of cool cinereous colours in which blue predominates,” while Field reserves grey to describe a more neutral shade. However, such nuanced distinctions are not observed in popular usage today.
EL James’s best-selling 2001 novel Fifty Shades of Grey, along with the blockbuster film of the same name released in 2015, may have contributed to increased uncertainty—some gray areas, if you will—about how to spell the term in recent years.
So, when it comes to the tones between black and white, both grey and gray are acceptable spellings in the English language. If you do find yourself trying to remember which side of the pond uses which spelling more often, keep in mind this mnemonic trick: England begins with an E, while America begins with an A.