Meanings
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1
noun
either of the male reproductive glands that produce sperm and secrete hormones such as testosterone
Each testis contains tightly coiled tubules in which sperm cells develop.
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2
noun
an analogous sperm-producing organ in an invertebrate
The biologist examined the testis of the insect for radiation-induced mutations.
Thesaurus
Etymology
A learned borrowing from Latin testis ("witness; testicle"). The anatomical sense may reflect the paired organs as witnesses of virility, although the precise semantic development in Latin is uncertain. The regular Latin plural, retained in scientific English, is testes.