The following definitions are found in Stedman's Medical Dictionary (Lippincott, Williams and Wilkins Publishers, 2002). Ablation Removal of a body part or the destruction of its function, as by a surgical procedure, morbid process, or noxious substance. Cryocautery Any substance, such as liquid nitrogen or carbon dioxide snow, or a low-temperature instrument, the application of which causes destruction of tissue by freezing. Endometrial ablation Therapeutic selective endometrial destruction. Endometrium The mucous membrane comprising the inner layer of the uterine wall; it consists of a simple columnar epithelium and a lamina propria that contains simple tubular uterine glands. The structure, thickness, and state of the endometrium undergo marked change with the menstrual cycle. Hysteroscope An endoscope used in direct visual examination of the uterine cavity. Thermal Pertaining to heat.