• WordNet 3.6
    • n homology the quality of being similar or corresponding in position or value or structure or function
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Webster's Revised Unabridged Dictionary
    • Homology (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 (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.
    • Homology The quality of being homologous; correspondence; relation; as, the homologyof similar polygons.
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Century Dictionary and Cyclopedia
    • n homology The state or character of being homologous; correspondence. Specifically— In biology, that relation between parts which results from their development from corresponding embryonic parts, either in different animals, as in the case of the arm of man, the fore leg of a quadruped, and the wing of a bird, or in the same animal, as in the case of the fore and hind legs in quadrupeds, or of the segments or rings and their appendages of which the body of a worm, a centiped, etc., is composed. Homology in this sense implies genetic relationship, and consequently morphological likeness or structural affinity; and it is distinguished from analogy, which usually results from physiological adaptation of unlike parts to like functions, and therefore implies a merely adaptive modification, which brings about a superficial resemblance between things quite unlike in structure, as between the wing of a bird and that of a butterfly. Several kinds of homology are distinguished: general, which is the relation of an organism, or of any of its parts, to the general type or plan of such organisms or parts; serial, which is the correspondence of metamerically multiplied parts in any organism, as of successive ribs, legs, vertebræ, etc., with one another; special, which is the correspondence of a part or organ of one animal with the same part in another, as the homology between a horse's fore “knee” and the humau wrist, etc. See homologous, homologue.
    • n homology In geometry, the relation between two corresponding figures lying in the same plane which are such that corresponding points are collinear With a fixed point called the center of homology, while corresponding lines intersect on a fixed line called the axis of homology.
    • n homology In chem., the relationship which the members of a homologous series bear to one another.
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Chambers's Twentieth Century Dictionary
    • Homology the quality of being homologous: affinity of structure, and not of form or use
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Webster's Revised Unabridged Dictionary
Gr. agreement. See Homologous
Chambers's Twentieth Century Dictionary
Gr. homologoshomos, the same, legein, to say.


In literature:

He will surely come to this from Homology and Embryology.
"The Life and Letters of Charles Darwin, Volume II (of II)" by Charles Darwin
I rather doubt whether you see how far, as it seems to me, the argument for homology and embryology may be carried.
"More Letters of Charles Darwin" by Charles Darwin
I must not now indulge myself with looking after vessels and homologies.
"More Letters of Charles Darwin Volume II" by Charles Darwin
Happily, however, there is a criterion of morphological truth, and a sure test of all homologies.
"Lectures and Essays" by T.H. Huxley
There are strange analogies; it may be that there are homologies.
"African and European Addresses" by Theodore Roosevelt
The chief erogenous zone in the female child is the clitoris, which is homologous to the male penis.
"Three Contributions to the Theory of Sex" by Sigmund Freud
They are called homologous because they have similar parts in similar relations.
"The Story of the Living Machine" by H. W. Conn
Happily, however, there is a criterion of morphological truth, and a sure test of all homologies.
"Lay Sermons, Addresses and Reviews" by Thomas Henry Huxley
It consists of a mixture of homologous hydrocarbons, which form a solid under ordinary conditions.
"Scientific American Supplement, No. 711, August 17, 1889" by Various
But the sets of homologous quantities running through the various terms of the series do converge to definite limits.
"The Concept of Nature" by Alfred North Whitehead

In news:

A team at the University of Colorado, Boulder, and Xiamen University in China has now shown that HBx interacts with the anti- apoptotic proteins Bcl-2 and Bcl-xL through a Bcl-2 homology 3 (BH3)-like motif in mammalian cells.
While the Cygnet is a Europe-only offering, Aston is actively considering taking it to the US Toyota is homologating the Scion iQ for this market, which acts in the Cygnet 's favor.
Structural Basis for Discrimination of 3-Phosphoinositides by Pleckstrin Homology Domains.
Structural Basis of 3-Phosphoinositide Recognition by Pleckstrin Homology Domains.
Analysis of sequence and structure homologies between thyroglobulin and acetylcholinesterase: Possible functional and clinical significance.
As noted above, the effectiveness of combination platinum/PARP inhibitor therapy may not require a homologous recombination repair defect.
Knowing the number of residue contacts in a protein is crucial for deriving constraints useful in modeling protein folding and/or scoring remote homology search.
Development of key high-throughput technologies: Structure prediction and homology modeling.

In science:

Rack and quandle (co)homology has been generalized in various ways including twisted quand le (co)homology in , quandle (co)homology with coefficients in quandle modules in and more.
Link invariants from finite racks
This implies that the distance between gD and wnD grows linearly in n, so by choosing a random walk supported on the Torelli group, the homology of M (wn g ) is the same as that of M (g ), so we can create random Heegaard splittings which are homology spheres, or which have the homology of any fixed 3-manifold.
Random Heegaard splittings
We shall check them making use of the corresponding axioms for definable sets through an adaptation of a classical result in homology that (roughly) states that the homology commutes with direct limits.
Locally definable homotopy
Solberg, Relative homology and representation theory I, Relative homology and homological ly finite subcategories, Comm.
Mutation of Auslander generators
Our goal is to generalize these ideas to the case when K is not null-homologous in M (that is, [K ] (cid:54)= 0 ∈ H1 (M ; Z)), in particular, to the case when K is homologous to another fixed knot J .
A Homological Approach to Relative Knot Invariants