plec·trum (plěk'trəm) n.
pl.plec·trums or plec·tra (-trə) A small thin piece of metal, plastic, bone, or similar material, used to pluck the strings of certain instruments, such as the guitar or lute.
[Latin plēctrum, from Greek plēktron, from plēssein, plēg-, to strike; see plāk-2 in Indo-European roots.]