An ancestor that two people have in common. For instance, first cousins all share a common grandfather, who would be a common ancestor. For Y-DNA comparisons, a common ancestor refers to a common paternal-line ancestor.

The most recent ancestral form or species from which two different species evolved.

An ancestor shared by any two people

person through whom tow or more persons claim descent or lineage.

An ancestor, often only known from fossil remains, from which two or more different species or lines of species are thought to have evolved.

one shared by two people.

Mutual ancestor of two or more persons