Cryonics is the practice of freezing a dead body in the hope that future scientific research will make it possible to bring the person back to life one day. Many scientists are skeptical about cryonics.
While there are some people who believe strongly that cryonics is a scientific way to preserve a human body, usually within minutes after the person's heart has stopped beating, mainstream scientists are generally doubtful that technology will ever allow for the defrosting and reanimating of these frozen bodies. Currently, there are a few hundred bodies that have been frozen through cryonics. The Greek root of cryonics is kryos, "icy cold."