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 (hə-mŏl′ə-jē, hō-)
n. pl. ho·mol·o·gies
1. The quality or condition of being homologous.
2. A homologous relationship or correspondence.
3. Chemistry
a. The relation of the elements of a periodic family or group.
b. The relation of the organic compounds forming a homologous series.
4. Mathematics A topological classification of configurations into distinct types that imposes an algebraic structure or hierarchy on families of geometric figures.

[Greek homologiā, agreement, from homologos, agreeing; see homologous.]


n, pl -gies
1. the condition of being homologous
2. (Chemistry) chem the similarities in chemical behaviour shown by members of a homologous series
3. (Zoology) zoology the measurable likenesses between animals, as used in grouping them according to the theory of cladistics
[C17: from Greek homologia agreement, from homologos agreeing; see homologate]


(həˈmɒl ə dʒi, hoʊ-)

n., pl. -gies.
1. the state of being homologous.
2. Biol.
a. a fundamental similarity based on common descent.
b. a structural similarity of two segments of one animal based on a common developmental origin.
3. the similarity of organic compounds of a series in which each member differs from successive compounds by a fixed increment, as by CH2.
4. a classification of mathematical figures according to certain topological properties.
[1650–60; < Greek homología agreement, derivative of homólog(os) homologous]


1. similarity of form or structure in two or more organisms owing to common descent.
2. similarity in form or structure between different parts of an organism owing to common origin. Cf. homodynamy.homologous, adj.
See also: Biology
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.homology - the quality of being similar or corresponding in position or value or structure or function
similarity - the quality of being similar
References in classic literature ?
What can be more singular than the relation between blue eyes and deafness in cats, and the tortoise-shell colour with the female sex; the feathered feet and skin between the outer toes in pigeons, and the presence of more or less down on the young birds when first hatched, with the future colour of their plumage; or, again, the relation between the hair and teeth in the naked Turkish dog, though here probably homology comes into play?
to the geometric realization [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII], and hence we have the map between the homology groups [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII].
The first sequence targeted internal transcribed spacer regions of ribosomal genes and revealed up to 100% homology with D.
They begin with basic definitions and then address three-dimensional topology, distributive groupoids, the Jones-Kauffman polynomial atoms, Khovanov homology, virtual braids, Vassilierv's invariants and framed graphs, parity, and theory of graph-links.
1142) examined interactions between the Tox21 pilot-phase collection of almost 3,000 environmental chemicals profiled in qHTS format and a panel of human nuclear receptors for reproducibility, concordance of biological activity profiles with sequence homology of the receptor ligand binding domains, and structure--activity relationships.
The first product available will be Equinox's leading Phyre(TM) homology modelling and fold-recognition software.
This fact has been illustrated with the help of the figures given in Table-2 which show the homology of Laspeyres and Paasche index numbers.
The concept of homology and its central role in the elucidation of plant systematic relationships.
This work offers a geometric introduction to the homology of topological spaces and the cohomology of smooth manifolds, and introduces a new class of stratified spaces called stratifolds.
Fred Hutchinson Cancer Research Center (Seattle, WA) has patented a mammalian homology of Drosophila Disabled protein has been identified and cloned.
Mathematicians are now finding that the Euler characteristic and a more complex topological tool called homology can solve many problems about wireless sensor networks.