ancestor  [  an-ses-ter or, especially British, -suh-ster ]

Synonyms: forebear, forefather, foremother, founder, antecedent, ascendant, forerunner, progenitor, etc.

Definition of ancestor

noun

1. 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.This machine is the ancestor of the modern computer.

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.