Ho-mŏl′o-gy, n.

n. [Gr. ὁμολογία, agreement. See supra.]

1. The quality of being homologous; correspondence; relation; as, the homology of similar polygons.
2. (Physiol.) Correspondence or relation in type of structure; as, the relation in structure between the leg and arm of man; or that between the arm of a man, fore leg of a horse, wing of a bird, and fin of a fish, the structures of all these organs being due to modifications of one type of structure.

☞ Homology differs from analogy, which is a relation or correspondence in functions: there is analogy between the wing of a bird and that of a bat, but not homology. Dana.