grayback vs greyback

grayback and greyback both are nouns.

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

As nouns, grayback and greyback are synonyms defined as:

Other synonyms of grayback include Limnodromus griseus.

As nouns, grayback and greyback are synonyms defined as:

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

Other synonyms of grayback include Calidris canutus, knot.

grayback (noun)	greyback (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