dark chocolate vs bittersweet chocolate

dark chocolate and bittersweet chocolate both are nouns.

Word	Noun	Adjective	Verb	Adverb
dark chocolate	Yes	No	No	No
bittersweet chocolate	Yes	No	No	No

As nouns, dark chocolate and bittersweet chocolate are synonyms defined as:

dark chocolate and bittersweet chocolate: chocolate liquor with cocoa butter and small amounts of sugar and vanilla; lecithin is usually added

Other synonyms of dark chocolate include semi-sweet chocolate.

dark chocolate (noun)	bittersweet chocolate (noun)
chocolate liquor with cocoa butter and small amounts of sugar and vanilla; lecithin is usually added	chocolate liquor with cocoa butter and small amounts of sugar and vanilla; lecithin is usually added