oxford gray vs charcoal gray

oxford gray and charcoal gray both are nouns.

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

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

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

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