testis (n.), testicular (adj.)

synonym: testicle
https://doi.org/10.1351/goldbook.11295

Gonad of a male animal, involved in the secretion of androgens and the site of sperm production.

Source:
PAC, 2016, 88, 713. (Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)) on page 812 [Terms] [Paper]