# homologous
## English
### Etymology

From Late Latin homologus, from Ancient Greek ὁμόλογος (homólogos, “agreeing, of one mind”), from ὁμός (homós, “same”) + λόγος (lógos, “reason, reckoning”). Compare homo- (“same”) and -ous (adjectival suffix). From 1655, in the mathematical sense. See also homolog, homologue.

### Pronunciation

* IPA: /həˈmɒləɡəs/
* Audio (US):(file)

### Adjective

homologous (comparative more homologous, superlative most homologous)
* Showing a degree of correspondence or similarity.
** (mathematics) In corresponding proportion.
    Coordinate term: homomorphic
*** 1655, Thomas Stanley, “[Thales.] Chapter VII. Of His Geometry.”, in The History of Philosophy. […], volume I, London: […] Humphrey Moseley, and Thomas Dring, […], →OCLC, 1st part ([Containing Those on whom the Attribute of Wise was Conferr’d]), page 18:Of equiangle triangles, the ſides that are about equall angles are proportionall, and the ſides that ſubtend the equall angles are homologous.
** (biology) Corresponding to a similar structure in another life form with a common evolutionary origin.
    Coordinate terms: heterologous, homoeologous; homomorphic
    Flippers and hands are homologous structures.
*** 1992, Rudolf M[athias] Schuster, The Hepaticae and Anthocerotae of North America: East of the Hundredth Meridian, volume V, Chicago, Ill.: Field Museum of Natural History, →ISBN, page 4:Lobules, homologous in structure, recur again only in the Gondwanalandic families Lepidolaenaceae and Jubulopsidaceae thus in the Lepidolaenineae.
** (chemistry) Belonging to a series of aliphatic organic compounds that differ only by the addition of a CH₂ group.
** (genetics) Having the same morphology as another chromosome or locus; relating to a homologue.
** (cultural anthropology, structural anthropology) Playing the same role as seen in another culture, whether by historical connection, psychological archetype, convergent cultural evolution, or otherwise (as may be hypothesized but not known with certainty by current science), as for example with the cryptozoologic concepts of yeti and sasquatch, the use of polite and familiar pronouns, or other similarities.

#### Usage notes

* (biology) For a discussion of the use of the term "homology" (and 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. https://web.archive.org/web/20180605014921/http://mbe.oxfordjournals.org/cgi/reprint/5/6/603.pdf(accessed 18 December 2009; archived 18 December 2009, )

#### Antonyms

* heterologous

#### Coordinate terms

* homoeologous

#### Derived terms

* cohomologous
* homologisation
* homologous blood donation
* homologously
* homologous pair
* homologous recombination
* homologous series
* interhomologous
* microhomologous
* nonhomologous

#### Related terms

* autologous
* homologation
* homolog, homologue
* homologize
* homology

#### Translations
### References

* ↑ Douglas Harper (2001–2025) “homologous”, in Online Etymology Dictionary.
* ↑ “homologous”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.
* ↑ Earliest Known Uses of Some of the Words of Mathematics (H)