Definition of Testis

Testis: The male sex gland, located behind the penis in a pouch of skin called the scrotum. The testes produce and store sperm and are also the body's main source of male hormones, such as testosterone. These hormones control the development of the reproductive organs and other male characteristics, such as body and facial hair, low voice, and wide shoulders. Also known as testicle.

Source: MedTerms™ Medical Dictionary
http://www.medterms.com/script/main/art.asp?articlekey=8975
Last Editorial Review: 3/19/2012