A prolapse is when a part inside the body slips down from the place where it usually sits. The organ is still attached; it has not fallen off — the muscles and tissue that hold it up have grown weak, so it droops. Doctors talk most often about the womb (a uterine prolapse), but the bladder, the bowel, and a disc in the spine can prolapse too. It is a medical word, used in clinics and health articles, not in casual chat. People also use it as a verb for the same thing: the disc has prolapsed. Though actually, in everyday talk a back problem of this kind is more often called a slipped disc, even when the doctor writes prolapse. It is not a bone popping out of a joint (that is a dislocation), and it is not the whole body collapsing.