WordNet
n. a plectrum used to pluck a guitar
Wikipedia
A guitar pick (American English) is a plectrum used for guitars. Picks are generally made of one uniform material—such as some kind of plastic ( nylon, Delrin, celluloid), rubber, felt, tortoiseshell, wood, metal, glass, tagua, or stone. They are often shaped in an acute isosceles triangle with the two equal corners rounded and the third corner less rounded. They are used to strum chords or to sound individual notes on a guitar.
In British English, guitar picks are referred to as plectrums reserving the term "pick" to identify the difference between this and finger picks.
Usage examples of "guitar pick".
Buddy was still inside the Sony, looking around as though he might have dropped his guitar pick.
He dropped to one knee, moved aside a clump of ivy, and showed us a guitar pick.
A couple of crumpled receipts, a faux-tortoiseshell guitar pick, loose change.
The Phaeacia resembled a giant guitar pick -- a reflective ellipsoid seventy-one meters long, thirty-three wide, and somewhat thicker aft than foreward.