Davy's gray vs Davy's grey

Davy's gray and Davy's grey both are nouns.

Word	Noun	Adjective	Verb	Adverb
Davy's gray	Yes	No	No	No
Davy's grey	Yes	No	No	No

As nouns, Davy's gray and Davy's grey are synonyms defined as:

Other synonyms of Davy's gray include iron blue, steel gray, steel grey.

Davy's gray (noun)	Davy's grey (noun)
slightly purplish or bluish dark grey	slightly purplish or bluish dark grey