Homology

A homologous^[1] trait is any characteristic which is derived by evolution from a common ancestor. This is contrasted to analogous traits: similarities between organisms that were evolved separately.

The term existed before 1859, but got its modern meaning after Darwin established the idea of common descent.^[2]p45 The pre-Darwinian naturalists Cuvier, Geoffroy and Richard Owen, also used the idea.

A homologous trait is often called a homologue (also spelled homolog). In genetics, the term "homologue" is used both to refer to a homologous protein, and to the gene (DNA sequence) encoding it.

1. ↑ Greek ομολογειν = 'to agree'
2. ↑ Mayr, Ernst 1982. The growth of biological thought. Harvard.