capo(n = noun.person) - the head of a branch of an organized crime syndicate;
is a kind of chief, head, top dog
capo, n. (in full capo tasto) (pl. capos or capo tastos) Mus. a device secured across the neck of a fretted instrument to raise equally the tuning of all strings by the required amount.
Etymology:
It. capo tasto head stop