[more ancient; most ancient], 1 : very old : having lived or existed for a very long time, The people in the village still observe the ancient customs/traditions of their ancestors. a grove of ancient oak trees, — often used in an exaggerated way to describe an old machine, person, etc. We got a ride in an ancient truck. an ancient barn, I never thought I'd feel ancient at age 31. She finally decided to replace her ancient computer with something more modern and up to date. 2 : of, coming from, or belonging to a time that was long ago in the past, The practice was more common in ancient times than it is now. life in ancient Egypt/Rome/Greece/China, the gods of the ancient Romans, ◊ In informal use, something that happened long ago and that is not important any more is ancient history. Our relationship is ancient history. Forget about the problems we've had in the past. They're ancient history.