Cryonics is the cryopreservation of corpses in the belief that resuscitation may eventually become possible in the future. There is no scientific evidence to support such hopes for human bodies preserved with currently available technology, although some extremophile microbes and invertebrates can survive storage in liquid nitrogen.
The term is often confused with cryogenics, the field concerned with producing temperatures at or below the boiling points of permanent gases (i.e. below about 90 K). Both derive from the Greek word κρύος (kryos), meaning cold.