brick red vs burnt sienna

brick red and burnt sienna both are nouns.

Word	Noun	Adjective	Verb	Adverb
brick red	Yes	No	No	No
burnt sienna	Yes	No	No	No

As nouns, burnt sienna is a hypernym of brick red; that is, burnt sienna is a word with a broader meaning than brick red:

Other hypernyms of brick red include mahogany, reddish brown, sepia, Venetian red.

brick red (noun)	burnt sienna (noun)
a bright reddish-brown color	a shade of brown with a tinge of red
	a reddish-brown pigment produced by roasting sienna