a pin of wood or other material driven or fitted into something, as to fasten parts together, to hang things on, to make fast a rope or string on, to stop a hole, or to mark some point.

Informal. a leg, either real or wooden: still on his pegs at 99.

a notch or degree: to come down a peg.

an occasion, basis, or reason: a peg to hang a grievance on.

Also called pin. Music. a pin of wood or metal in the neck of a stringed instrument that may be turned in its socket to adjust a string's tension.