testicle

Etymology

Borrowed from Latin testiculus, diminutive of testis.

noun

1. A testis: the male sex and endocrine gland, found in some types of animals, that produces sperm and male sex hormones, including the steroid testosterone.
   Despite your jogging and the hairiness of your legs, the shoe of aging is beginning to pinch. Soon you'll regret all that sun-tanning. Your face will look like a testicle. 2000, Margaret Atwood, The Blind Assassin, page 372
2. (more commonly) Either half of the structure that contains the testes: one side of the scrotum and its contents, considered as one object (one half of the ballsack, including its ball).