Homology
Homology Ho*mol"o*gy, n. [Gr. ? agreement. See {Homologous}.] 1. The quality of being homologous; correspondence; relation; as, the homologyof similar polygons. [1913 Webster]

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. [1913 Webster]

Note: Homology indicates genetic relationship, and according to Haeckel special homology should be defined in terms of identity of embryonic origin. See {Homotypy}, and {Homogeny}. [1913 Webster]

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}. [1913 Webster]

{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. [1913 Webster]


The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • Homology — may refer to:* Homology (anthropology), analogy between human beliefs, practices or artifacts due to genetic or historical connections. * Homology (biology): similar structures due to shared ancestry. * Homology (chemistry): a compound of a… …   Wikipedia

  • homology — homology. См. гомология. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • homology — index analogy, relation (connection) Burton s Legal Thesaurus. William C. Burton. 2006 …   Law dictionary

  • homology —   , homology.   Features having a common origin but not necessarily the same function, e.g. cycad leaves, cataphylls, and sporophylls.   See also apomorphy, autoapomorphy, homoplasy, plesiomorphy, symplesiomorphy, synapomorphy …   Expanded glossary of Cycad terms

  • homology — [hō mäl′ə jē, həmäl′ə jē] n. pl. homologies [LL homologia < Gr: see HOMO & LOGY] 1. the quality or state of being homologous 2. a homologous correspondence or relationship, as of animal organs, chemical compounds, etc …   English World dictionary

  • homology — /heuh mol euh jee, hoh /, n., pl. homologies. 1. the state of being homologous; homologous relation or correspondence. 2. Biol. a. a fundamental similarity based on common descent. b. a structural similarity of two segments of one animal based on …   Universalium

  • homology — noun (plural gies) Date: circa 1656 1. a similarity often attributable to common origin 2. a. likeness in structure between parts of different organisms (as the wing of a bat and the human arm) due to evolutionary differentiation from a… …   New Collegiate Dictionary

  • homology — homologija statusas T sritis augalininkystė apibrėžtis Darinių panašumas dėl artimos kilmės. atitikmenys: angl. homology rus. гомология …   Žemės ūkio augalų selekcijos ir sėklininkystės terminų žodynas

  • homology — homologous ► ADJECTIVE 1) having the same relation, relative position, or structure. 2) Biology (of organs) similar in position, structure, and evolutionary origin. DERIVATIVES homologize (also homologise) verb homology noun. ORIGIN Greek… …   English terms dictionary

  • homology — similarity of characters due to close ancestry, a common evolutionary origin, e.g. pectoral fins are homologous with human arms but pelvic fins are not homologous with legs (and so are perhaps better termed ventral fins). In contrast to homoplasy …   Dictionary of ichthyology

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