Testis (noun)

1. The male reproductive organ that produces sperm and testosterone in mammals, birds and reptiles.
2. The witness in a legal proceeding.

Origin:

From latin testis, meaning witness.

Examples:

1. The testis is located in the scrotum.
2. The testis is responsible for producing sperm which is necessary for reproduction.
3. The testis are considered as the primary reproductive organ in males.
4. The testis produce testosterone which is responsible for the development of male secondary sexual characteristics.
5. He was a testis in the court case and testified about what he had seen.