Definition of: ancestor

(an′ses·tər) noun
1. One from whom descent is derived; especially, such person further back in the line than a grandparent; forefather; progenitor; forebear.
2. Law One who precedes another in the line of legal inheritance, whether or not a direct progenitor: correlative of heir.
3. Biol. An actual or hypothetical organism from which subsequent types have developed; a prototype. [ < OF ancestre < L antecessor < antecedere <ante- before + cedere go]