A diaphragm is a thin, flexible barrier used in various applications, including medicine and contraception. In the medical field, it refers to a muscle located beneath the lungs that plays a crucial role in breathing. When the diaphragm contracts, it creates a vacuum that allows air to flow into the lungs. In contraception, a diaphragm is a dome-shaped device made of silicone or latex that is inserted into the vagina to cover the cervix. It acts as a barrier to prevent sperm from entering the uterus, and it is often used with spermicide for increased effectiveness.