"Spaying" and "neutering" are surgical procedures used to prevent pets from reproducing. In a female animal, "spaying" consists of removing the ovaries or uterus and ovaries. The technical term is ovariectomy or ovariohysterectomy. For a male animal, "neutering" involves the removal of the testicles, and this is known as castration.
In addition to preventing unwanted offspring, spaying or neutering has many health and behavioural benefits to the animal.