Chapter Homœozoic to Hone of H by Webster's Dictionary (1913 Edition)

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

(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.

Homolographic
(Hom`o*lo*graph"ic) a. [Homo- + Gr. "o`los whole + -graph + -ic; but cf. F. homalographique, Gr. even, level.] Preserving the mutual relations of parts, especially as to size and form; maintaining relative proportion.

Homolographic projection, a method of constructing geographical charts or maps, so that the surfaces, as delineated on a plane, have the same relative size as the real surfaces; that is, so that the relative actual areas of the different countries are accurately represented by the corresponding portions of the map.

Homologue
(Hom"o*logue) n. [Cf. F. homologue. See Homologous.] That which is homologous to something else; as, the corresponding sides, etc., of similar polygons are the homologues of each other; the members or terms of an homologous series in chemistry are the homologues of each other; one of the bones in the hand of man is the homologue of that in the paddle of a whale.

Homology
(Ho*mol"o*gy) n. [Gr. agreement. See Homologous.]

1. The quality of being homologous; correspondence; relation; as, the homologyof similar polygons.

2. (Biol.) Correspondence or relation in type of structure in contradistinction to similarity of function; as, the relation in structure between the leg and arm of a man; or that between the arm of a man, the fore leg of a horse, the wing of a bird, and the fin of a fish, all these organs being modifications of one type of structure.

Homology indicates genetic relationship, and according to Haeckel special homology should be defined in terms of identity of embryonic origin. See Homotypy, and Homogeny.

3. (Chem.) The correspondence or resemblance of substances belonging to the same type or series; a similarity of composition varying by a small, regular difference, and usually attended by a regular variation in physical properties; as, there is an homology between methane, CH₄, ethane, C₂H₆, propane, C₃H₈, etc., all members of the paraffin series. In an extended sense, the term is applied to the relation between chemical elements of the same group; as, chlorine, bromine, and iodine are said to be in homology with each other. Cf. Heterology.

General homology (Biol.), the higher relation which a series of parts, or a single part, bears to the fundamental or general type on which the group is constituted. Owen. — Serial homology (Biol.), representative or repetitive relation in the segments of the same organism, — as in the lobster, where the parts follow each other in a straight line or series. Owen. See Homotypy. — Special homology (Biol.), the correspondence of a part or organ with those of a different animal, as determined by relative position and connection. Owen.