The definition of homology is two or more things having the same position or structure.
An example of homology in biology is the human arm and the wing of a bird.
- the quality or state of being homologous
- a homologous correspondence or relationship, as of animal organs, chemical compounds, etc.
Origin of homologyLate Latin homologia ; from Gr: see homo- and amp; -logy
- The quality or condition of being homologous.
- A homologous relationship or correspondence.
- Chemistry a. The relation of the elements of a periodic family or group.b. The relation of the organic compounds forming a homologous series.
- Mathematics A topological classification of configurations into distinct types that imposes an algebraic structure or hierarchy on families of geometric figures.
Origin of homologyGreek homologia, agreement, from homologos, agreeing; see homologous.
- A homologous relationship.
- (biology) A correspondence of structures in two life forms with a common evolutionary origin, such as flippers and hands.
- (chemistry) The relationship between the elements in the same group of the periodic table, or between organic compounds in a homologous series.
- (mathematics) A theory associating a system of quotient groups to each topological space.
- (mathematics) A system of quotient groups associated to a topological space.
- (genetics) The presence of the same series of bases in related genes.
- Like many terms that start with a (non-silent) h and have emphasis on their second syllable, some people precede homology with an, others with a.
- (biology): For a discussion of the use of the term homology (by association homologous) in biology, see: Patterson, Colin. "Homology in Classical and Molecular Biology." Molecular Biology and Evolution 5, no. 6 (November 1988): 603–625. http://mbe.oxfordjournals.org/cgi/reprint/5/6/603.pdf (accessed 18 December 2009; archived 18 December 2009, http://www.webcitation.org/5m7rn4rCe)
- (mathematics): When used attributively before the name of a topological space, as in "homology n-sphere" or "homology manifold", the reference is to a space whose homology is the same as that of the space mentioned: an homology manifold, for example, is a space whose homology is that of some manifold.