Wiktionary
cervical cap
n. a small, latex or silicone, contraceptive device that fits over the cervix and stays in place either by suction, like Prentif or by surface viscosity, like Oves.
WordNet
cervical cap
n. a contraceptive device consisting of a small thimble-shaped cup that is placed over the uterine cervix to prevent the entrance of spermatozoa