charcoal gray vs oxford gray

charcoal gray and oxford gray both are nouns.

Word	Noun	Adjective	Verb	Adverb
charcoal gray	Yes	No	No	No
oxford gray	Yes	No	No	No

As nouns, charcoal gray and oxford gray are synonyms defined as:

Other synonyms of charcoal gray include charcoal, charcoal grey, oxford grey.

charcoal gray (noun)	oxford gray (noun)
a very dark grey color	a very dark grey color