orthogenesis

noun

or·​tho·​gen·​e·​sis ˌȯr-thə-ˈje-nə-səs How to pronounce orthogenesis (audio)
: variation of organisms in successive generations that in some especially former evolutionary theories takes place in some predestined direction resulting in progressive evolutionary trends independent of external factors
orthogenetic
ˌȯr-thə-jə-ˈne-tik How to pronounce orthogenesis (audio)
adjective
orthogenetically
ˌȯr-thə-jə-ˈne-ti-k(ə-)lē How to pronounce orthogenesis (audio)
adverb

Examples of orthogenesis in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The various models proposed for the mechanism of evolution, such as Lamarckian evolution, orthogenesis, and use-disuse, all implied some level of teleology, that there was a directionality inherent in the process. — Mano Singham, Scientific American, 5 Sep. 2021 Sperm structure and motility in the eusocial naked mole-rat, Heterocephalus glaber: a case of degenerative orthogenesis in the absence of sperm competition? — Ed Yong, Discover Magazine, 4 Dec. 2011

Word History

Etymology

New Latin

First Known Use

1895, in the meaning defined above

Time Traveler
The first known use of orthogenesis was in 1895

Rhymes for orthogenesis

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Browse Nearby Words

orthoformic ester
orthogenesis
orthogenetic
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Cite this Entry

“Orthogenesis.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/orthogenesis. Accessed 7 Jul. 2026.

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Medical Definition

orthogenesis

noun
or·​tho·​gen·​e·​sis ˌȯr-thə-ˈjen-ə-səs How to pronounce orthogenesis (audio)
plural orthogeneses -ˌsēz How to pronounce orthogenesis (audio)
: variation of organisms in successive generations that in some evolutionary theories takes place in some predestined direction and results in progressive evolutionary trends independent of external factors
orthogenetic
-jə-ˈnet-ik How to pronounce orthogenesis (audio)
adjective

More from Merriam-Webster on orthogenesis

Britannica.com: Encyclopedia article about orthogenesis

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