noun

1. One from whom a person is descended, whether on the father's or mother's side, at any distance of time; a progenitor; a forefather.

2. An earlier type; a progenitor

   “This fossil animal is regarded as the ancestor of the horse.”

3. One from whom an estate has descended;—the correlative of heir.

Synonyms: origin, reflex, source, fore-elder, forebear, forefather, predecessor

verb

1. To be an ancestor of.