‘Gray’ and ‘grey’ are both considered to be a correct spelling of the color that combines white and black. ‘Gray’ tends to be the spelling favored by U.S. native English speakers, while ‘grey’ is used more often in the U.K.
“I say, old chap, it’s a grey and rainy day today in London.”
Grey means an achromatic color that stands between black and white. Most people refer to it as ash because of its dreary and gloomy appearance.
"I can't seem to find my grey boots. I left it by the door when I came in."
Gray is an alternative spelling of the word, grey. It is accepted in official writings as it means the same as the latter.
"He bought his wife a pair of gray sunglasses for their anniversary."
Grey is actually a variant of gray. Both mean the same.
"There are as many shades of grey between black and white as there are gray strands in grandma's lock."