homologous

In biology, a term describing an organ or structure possessed by members of different taxonomic groups (for example, species, genera, families, orders) that originally derived from the same structure in a common ancestor. The wing of a bat, the arm of a monkey, and the flipper of a seal are homologous because they all derive from the forelimb of an ancestral mammal.

The wing of a bird and the wing of an insect are not homologous, even though they are both used for flying, because they are not derived from the same structure.