phthalic anhydride vs anhydride

phthalic anhydride and anhydride both are nouns.

Word	Noun	Adjective	Verb	Adverb
phthalic anhydride	Yes	No	No	No
anhydride	Yes	No	No	No

As nouns, anhydride is a hypernym of phthalic anhydride; that is, anhydride is a word with a broader meaning than phthalic anhydride:

phthalic anhydride: a white cyclic anhydride
anhydride: a compound formed from one or more other compounds in a reaction resulting in removal of water

phthalic anhydride (noun)	anhydride (noun)
a white cyclic anhydride	a compound formed from one or more other compounds in a reaction resulting in removal of water