tes·​tis | \ ˈte-stəs How to pronounce testis (audio) \
plural testes\ ˈte-​ˌstēz How to pronounce testis (audio) \

Definition of testis

: a typically paired male reproductive gland that produces sperm and secretes testosterone and that in most mammals is contained within the scrotum at sexual maturity

Examples of testis in a Sentence

Recent Examples on the Web Testosterone, which is produced in abundance by male testes, has been shown to tamp down inflammation. Author: Chris Mooney, Sarah Kaplan, Brady Dennis, Anchorage Daily News, "All across the United States, the coronavirus is killing more men than women, data show," 4 Apr. 2020 The best time to irradiate, the two found, was 5.5 to 5.7 days into the pupal stage, when the adult fly’s ovaries and testes were developing and thus most sensitive to radiation. Sarah Zhang, The Atlantic, "The U.S. Is Spending Millions of Dollars Rearing Flesh-Eating Worms," 26 May 2020 For example, adult male moths that hailed, as larvae, from a dense population develop particularly large testes. Cordelia Fine, Scientific American, "Promiscuous Men, Chaste Women and Other Gender Myths," 1 Sep. 2017 Scientists have speculated that its regulation in the testes might partially explain higher ACE2 concentrations in men, and why men are more vulnerable to COVID-19. Fox News, "Men have high levels of enzyme key to COVID-19 infection, study finds," 12 May 2020 While women offer the coronavirus plenty of opportunities to enter their cells, men’s testes may give the virus an extra point of entry. Los Angeles Times, "Do testicles make men more vulnerable to the coronavirus?," 18 Apr. 2020 The study, which was published Thursday in the journal Cell, relied on samples—testis, liver, and brain—from two wild koalas that had KoRV. Andrew Joseph, Scientific American, "What a Koala Virus Tells Us about the Human Genome," 14 Oct. 2019 And since sperm production is dependent on very high testosterone levels in the testes (much higher than the testosterone levels in the blood), shutting the gonadotropins lowers sperm production. Julia Belluz, Vox, "A pill, a gel, and a nonsurgical vasectomy are making their way through clinical trials.," 4 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'testis.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of testis

1650, in the meaning defined above

History and Etymology for testis

Latin, witness, testis

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Time Traveler for testis

Time Traveler

The first known use of testis was in 1650

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Statistics for testis

Cite this Entry

“Testis.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/testis. Accessed 18 Jan. 2021.

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More Definitions for testis


tes·​tis | \ ˈte-stəs How to pronounce testis (audio) \
plural testes\ ˈte-​ˌstēz \

Kids Definition of testis

: a male reproductive gland that produces sperm


tes·​tis | \ ˈtes-təs How to pronounce testis (audio) \
plural testes\ ˈtes-​ˌtēz How to pronounce testis (audio) \

Medical Definition of testis

: a typically paired male reproductive gland that usually consists largely of seminiferous tubules from the epithelium of which spermatozoa develop, that contains androgen-secreting Leydig cells in the interstitial tissue, that corresponds to the ovary of the female and in craniate vertebrates develops from the genital ridges of the embryo, and that in most mammals descends into the scrotum before the attainment of sexual maturity and in many cases before birth

More from Merriam-Webster on testis

Britannica.com: Encyclopedia article about testis

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