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 (https://doi.org/10.1515/pac-2015-1202)