What does ancestor mean?
The definition of ancestor
An”ces*tor, n.
Etym: [OE. ancestre, auncestre, also ancessour; the first forms fr. OF. ancestre, F. ancêtre, fr. the L. nom. antessor one who goes before; the last form fr. OF. ancessor, fr. L. acc. antecessorem, fr. antecedere to go before; ante before + cedere to go. See Cede, and cf. Antecessor.]

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 fore father.
2 (Biol.)
An earlier type; a progenitor; as, this fossil animal is regarded as the ancestor of the horse.
3 (Law)
One from whom an estate has descended; — the correlative of heir.