testosterone tes·tos·ter·one (těs-tŏs'tə-rōn')
n.
A steroid hormone and the most potent naturally occurring androgen that is formed by the interstitial cells of the testes, and possibly by the ovary and adrenal cortex, may be produced in nonglandular tissues from precursors such as androstenedione, and is used in the treatment of hypogonadism, cryptorchism, carcinomas, and menorrhagia.
A male hormone that governs secondary sex characteristics. It is produced in the testes.