Having lived for a long time; no longer young. The old man walked slowly down the street.
Belonging to the past; former. She wore an old dress that reminded her of her childhood.
Showing the effects of age or wear. The old book had yellowed pages and a worn cover.
Familiar or well-known from the past. It was nice to see an old friend after so many years.
Being a specified number of years (or other units of time) in age. The puppy is six months old.
Used before a noun to show affection, familiarity, or mild emphasis. Good old Sarah always knows how to cheer me up.