steel grey vs Davy's gray

steel grey and Davy's gray both are nouns.

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

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

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

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