What is the definition or description of: cryptorchidism?

Cryptorchidism: Is the failure of one or both testes to descend into the scrotum. It means undescended testicle/testicles.

Hidden testis: The testis develops in the abdomen during fetal life and descends all the way to the scrotum on both sides. Given this long journey, it is not surprising that 3% don't make it at birth. When the testis on one side or the other is non palpable, it is said to be cryptorchid. There is a 5% chance that it did not develop normally or that is atrophied from a loss of blood supply in utero (i.e. Torsion).

Hidden testicle: Cryptorchid testis is a type of undescended testis which can not be palpated/felt. It can be intra-abdominal, non-palpable in the inguinal canal, hidden by subcutaneous fat & occasionally ectopic. Can be confused with an absent testicle, which strictly is not cryptorchid because it is just absent.