ancestor

n. forefather, progenitor; forerunner; person who is related to a person existing at a later point in time; animal or plant from which other types evolved; (Law) person from whom an estate has descended

An ancestor is a parent or (recursively) the parent of an ancestor (i.e., a grandparent, great-grandparent, and so on). Two individuals have a genetic relationship if one is the ancestor of the other, or if they share a common ancestor. In evolutionary theory, species who share an evolutionary ancestor are said to be of common descent. However, this concept of ancestry does not apply to some bacteria and other organisms capable of horizontal gene transfer.
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Noun
1. someone from whom you are descended (but usually more remote than a grandparent)
(synonym) ascendant, ascendent, antecedent, root
(antonym) descendant, descendent
(hypernym) relative, relation
(hyponym) ancestress

(n.)
One from whom an estate has descended; -- the correlative of heir.
  

(n.)
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.
  

(n.)
An earlier type; a progenitor; as, this fossil animal is regarded as the ancestor of the horse.
  

noun
person from whom someone is descended, usually a person who lived a long time ago