Merriam-Webster's Collegiate® Dictionary, 11th Edition
CAPO
I. noun (plural capos)
Etymology: short for capotasto, from Italian, literally, head of fingerboard
Date: 1926
a movable bar attached to the fingerboard of a fretted instrument to uniformly raise the pitch of all the strings,
II. noun (plural capos)
Etymology: Italian, head, chief, from Latin caput
Date: circa 1952
the head of a branch of a crime syndicate