testis

noun

tes·​tis ˈte-stəs 

plural testes ˈte-ˌstēz 

: 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

Immune cells also invaded the testes, and inflammatory genes were switched on, indicating that the infection triggered an immune response in an organ that’s usually protected from such activity. —New Atlas, 13 Oct. 2025

The LNPs were injected carrying the Pdha2 mRNA into the rete testis to ensure broad delivery throughout the seminiferous tubules. —Mrigakshi Dixit, Interesting Engineering, 13 Oct. 2025

Once back on Earth, researchers injected the same spermatogonial stem cells — which are cells located in the testes that play a crucial role in sperm production — back into the testes of mice. —Jessica Rendall, Space.com, 29 Aug. 2025

The rest—less than 5 percent—is found in brain tissue and the testes. —Boutayna Chokrane, Wired News, 13 Aug. 2025

Word History

Etymology

Latin, witness, testis

First Known Use

1650, in the meaning defined above

Rhymes for testis

• asbestos
• hephaestus

Kids Definition

testis

noun

tes·​tis ˈtes-təs 

plural testes ˈtes-ˌtēz 

: an oval-shaped male reproductive gland that produces sperm and secretes testosterone and that in most mammals is contained within the scrotum

Medical Definition

testis

noun

tes·​tis ˈtes-təs 

plural testes ˈtes-ˌtēz 

: 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