phenobarbital vs barbiturate

phenobarbital and barbiturate both are nouns.

Word	Noun	Adjective	Verb	Adverb
phenobarbital	Yes	No	No	No
barbiturate	Yes	No	No	No

As nouns, barbiturate is a hypernym of phenobarbital; that is, barbiturate is a word with a broader meaning than phenobarbital:

phenobarbital: a long-acting barbiturate used as a sedative
barbiturate: organic compound having powerful soporific effect; overdose can be fatal

phenobarbital (noun)	barbiturate (noun)
a long-acting barbiturate used as a sedative	organic compound having powerful soporific effect; overdose can be fatal