The testis is the male generative organ, producing sperm cells and the male sex hormone, testosterone. Testis is a Latin word for “witness”, as in witnessing to one’s manhood. Did you know that the words testify, testimonial and testament share a common meaning with testis? So, when you testify you are witnessing to the truth. When you give a testimonial you are witnessing to the fine flavor or durability of some product and when you sign your last will and testament you are witnessing to your last wishes.
Orchis is the Greek name for the testis. Hence, medical terms contain the stem such as orchiditis (inflammation) and orchidectomy (removal) of the testis. Anatomical terms use the Latin form as in testicular artery and vein.