Grey Market or Grey Sheet Q & A

[bob41]

Gray vs. grey

Gray and grey are different spellings of the same word, and both are used throughout the English-speaking world. But gray is more common in American English, while grey is more common in all other major varieties of English.

Both spellings, which have origins in the Old English gr?g, have existed hundreds of years. The American–British distinction did not develop until the 19th century. As the Ngram at the bottom of this post shows, gray became the preferred spelling in American English around 1825.

The phrase grey area/gray area, meaning an area having characteristics of two extremes, may be spelled either way. Graybeard/greybeard, referring to an older man with a beard, is also spelled both ways. So is gray squirrel/grey squirrel. But greyhound—the breed of dog—is always spelled with an e.
Examples

For example, these American publications use gray:

Regional economic data released Tuesday highlighted just how many shades of gray now cloud the once-bright picture for emerging Asia. [NY Times]

When a Lincoln Navigator L with a gray interior arrived, Brown insisted on the black-on-black vehicle . . . [Washington Post]

Discipline has loopholes and gray areas. [Denver Post]

And these non-U.S. publications use grey:

The 41-year-old opted for a monochromatic look consisting of a short, charcoal grey dress … [Daily Mail]

Slap fresh bread around grey meat and it’s still a bad sandwich. [Globe and Mail]

The pressure also changed and the colour of the sky and sea transformed from metallic grey to a dust-red hue. [Guardian]

When it lives in the grey area between the two worlds, every day begins with a laborious examination of the numbers. [Sydney Morning Herald]

http://grammarist.com/spelling/gray-grey/