a person from whom one is descended; forebear; progenitor.
2.
Biology. the actual or hypothetical form or stock from which an organism has developed or descended.
3.
an object, idea, style, or occurrence serving as a prototype, forerunner, or inspiration to a later one: The balloon is an ancestor of the modern dirigible.
4.
a person who serves as an influence or model for another; one from whom mental, artistic, spiritual, etc., descent is claimed: a philosophical ancestor.
5.
Law.a person from whom an heir derives an inheritance.
c.1300, from O.Fr. ancestre (Mod.Fr. ancêtre), from L.L. antecessor "predecessor," lit. "foregoer," agent noun from L. antecessus, pp. of antecedere "precede," agent noun from ante- "before" (see ante) + cedere "to go" (see cede). Fem. form ancestress recorded from 1570s.