plectrum vs guitar pick

plectrum and guitar pick both are nouns.

Word	Noun	Adjective	Verb	Adverb
plectrum	Yes	No	No	No
guitar pick	Yes	No	No	No

As nouns, guitar pick is a hyponym of plectrum; that is, guitar pick is a word with a more specific, narrower meaning than plectrum:

plectrum: a small thin device (of metal or plastic or ivory) used to pluck a stringed instrument
guitar pick: a plectrum used to pluck a guitar

plectrum (noun)	guitar pick (noun)
a small thin device (of metal or plastic or ivory) used to pluck a stringed instrument	a plectrum used to pluck a guitar