bass guitar vs guitar

bass guitar and guitar both are nouns.

Word	Noun	Adjective	Verb	Adverb
bass guitar	Yes	No	No	No
guitar	Yes	No	No	No

As nouns, guitar is a hypernym of bass guitar; that is, guitar is a word with a broader meaning than bass guitar:

bass guitar: the guitar with six strings that has the lowest pitch
guitar: a stringed instrument usually having six strings; played by strumming or plucking

Other hypernyms of bass guitar include bass.

bass guitar (noun)	guitar (noun)
the guitar with six strings that has the lowest pitch	a stringed instrument usually having six strings; played by strumming or plucking