having the same evolutionary origin but not necessarily the same function
<adj.all> the wing of a bat and the arm of a man are homologous
corresponding or similar in position or structure or function or characteristics; especially derived from an organism of the same species
<adj.all> a homologous tissue graft
Homologous \Ho*mol"o*gous\, a. [Gr. ? assenting, agreeing; ? the same + ? speech, discourse, proportion, ? to say, speak.] Having the same relative position, proportion, value, or structure. Especially: (a) (Geom.) Corresponding in relative position and proportion.
In similar polygons, the corresponding sides, angles, diagonals, etc., are homologous. --Davies & Peck (Math. Dict.). (b) (Alg.) Having the same relative proportion or value, as the two antecedents or the two consequents of a proportion. (c) (Chem.) Characterized by homology; belonging to the same type or series; corresponding in composition and properties. See {Homology}, 3. (d) (Biol.) Being of the same typical structure; having like relations to a fundamental type to structure; as, those bones in the hand of man and the fore foot of a horse are homologous that correspond in their structural relations, that is, in their relations to the type structure of the fore limb in vertebrates.
{Homologous stimulus}. (Physiol.) See under {Stimulus}.