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 initial capital letters) a person in a position of authority, esp. an employer or a commanding officer: The Old Man has ordered an inspection for Saturday morning.
south·ern·wood (sŭth'ərn-wŏŏd') n. An aromatic southern European shrubby woody plant (Artemisia abrotanum) having finely divided grayish foliage and globose, nodding, creamy-white flower heads. Also called old man.
n. (one's) father. : What time does your old man get home?
n. (one's) husband. : My old man is sick and can't come with me.
n. (one's) boyfriend. : I got my old man to take me to see that movie I told you about.
n. the old man the boss; a high-ranking officer. (Always with the in this sense.) : The old man says do it, so you had better do it.
Dictionary of American Slang and Colloquial Expressions by Richard A. Spears.Fourth Edition. Copyright 2007. Published by McGraw Hill.
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) a person in a position of authority, esp. an employer or a commanding officer: The Old Man has ordered an inspection for Saturday morning. 
(sŭth'ərn-wŏŏd') 