copper color vs sepia

copper color and sepia both are nouns.

Word	Noun	Adjective	Verb	Adverb
copper color	Yes	No	No	No
sepia	Yes	No	No	No

As nouns, sepia is a hypernym of copper color; that is, sepia is a word with a broader meaning than copper color:

Other hypernyms of copper color include burnt sienna, mahogany, reddish brown, Venetian red.

copper color (noun)	sepia (noun)
a reddish-brown color resembling the color of polished copper	a shade of brown with a tinge of red
	rich brown pigment prepared from the ink of cuttlefishes