What does testis mean?
Testis is the formal anatomical term for a testicle, one of the paired male reproductive glands. In a typical human male, the two testes descend into the scrotum, where they produce sperm and most testosterone, along with other hormones. The singular is testis, while the standard plural is testes; “testises” is not conventional English. Outside anatomy, biology, and medical contexts, testicle is normally the more familiar word, whereas testis lends the term a technical or scholarly tone. Testis also appears in established medical wording, as in “undescended testis.” The word has an unusual history: it comes from Latin testis, which named the organ but also meant “witness.” The connection between those two Latin senses is debated, so the safest lesson is etymological rather than causal: the same Latin word carried both meanings. Today, testis remains useful in anatomy and clinical description, where precision about a male reproductive organ matters.
nounA testis is one of the paired male reproductive glands that produce sperm and most testosterone. The singular is chiefly used in anatomical and medical contexts.
- An anatomical testis: one of the two male reproductive glands, normally located in the scrotum, that produces sperm and most testosterone.
"The surgeon removed the affected testis and sent it for pathological examination."
"The patient had an undescended testis on the left."
"Each testis normally lies within the scrotum and is associated with an epididymis."
The standard plural is testes; “testises” is not standard English.
"Both testes appeared normal on the ultrasound."
One Latin word does double duty: testis means both “testicle” and “witness.”
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does testis come from?
Testis was borrowed into English from Latin testis, with plural testes, meaning “testicle.” Latin testis also meant “witness,” although the relationship between the two senses remains uncertain. English retained the Latin plural testes, while words such as testicle were formed from the Latin diminutive testiculus.
Related word forms
How testis is actually used
Testis is relatively uncommon in general conversation, where testicle is usually preferred. It is standard in anatomy, physiology, pathology, and clinical medicine and has a formal or technical tone.
Easily confused with testis
Testis is the singular form, while testes is the standard plural; testes is sometimes mistakenly treated as a separate singular noun.