A person from whom one is descended
One that precedes, as in time
It was their ancestor who wrote the letters I've got!
It's important for 'em to stay here—in the same place where ancestor Annie lived.
It was the natural yearning of that portion, any portion of our most primitive ancestor which still survived in us.
Possibly there is a trace of ancestor worship even here; but the two usages have diverged.
AEACUS, in Greek legend, ancestor of the Aeacidae, was the son of Zeus and Aegina, daughter of the river-god Asopus.