1. a father, usually one's own: His old man's letting him have the car for the prom.
2. a husband: The office is giving my old man a retirement party.
3. a boyfriend or male lover, esp. a male lover with whom one cohabits.
4. (sometimes caps.) a person in a position of authority, esp. an employer or a commanding officer: The Old Man has ordered an inspection for Saturday morning.
5. (used affectionately in addressing a man).
6. See old Adam.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.