'old man' definitions:

Definition of 'old man'

From: WordNet
noun
A man who is very old [syn: old man, greybeard, graybeard, Methuselah]
noun
A familiar term of address for a man [syn: old boy, old man]
noun
An informal term for your father
noun
Aromatic herb of temperate Eurasia and North Africa having a bitter taste used in making the liqueur absinthe [syn: common wormwood, absinthe, old man, lad's love, Artemisia absinthium]
noun
(slang) boss

Synonyms of 'old man'

From: Moby Thesaurus