greyback vs grayback

greyback and grayback both are nouns.

Word	Noun	Adjective	Verb	Adverb
greyback	Yes	No	No	No
grayback	Yes	No	No	No

As nouns, greyback and grayback are synonyms defined as:

Other synonyms of greyback include Limnodromus griseus.

As nouns, greyback and grayback are synonyms defined as:

greyback and grayback: a sandpiper that breeds in the Arctic and winters in the Southern Hemisphere

Other synonyms of greyback include Calidris canutus, knot.

greyback (noun)	grayback (noun)
a dowitcher with a grey back	a dowitcher with a grey back
a sandpiper that breeds in the Arctic and winters in the Southern Hemisphere	a sandpiper that breeds in the Arctic and winters in the Southern Hemisphere
`Johnny' was applied as a nickname for Confederate soldiers by the Federal soldiers in the American Civil War; `greyback' derived from their grey Confederate uniforms