Cryo
Cryo- is from the Ancient Greek κρύος (krúos, “ice, icy cold, chill, frost”).  Uses of the prefix Cryo- include:

Physics and geology
Cryogenics, the study of the production and behaviour of materials at very low temperatures and the study of producing extremely low temperatures
Cryoelectronics, the study of superconductivity under cryogenic conditions and its applications
Cryosphere, those portions of Earth's surface where water ice naturally occurs
Cryotron, a switch that uses superconductivity
Cryovolcano, a theoretical type of volcano that erupts volatiles instead of molten rock

Biology and medicine
Cryobiology, the branch of biology that studies the effects of low temperatures on living things
Cryonics, the low-temperature preservation of people who cannot be sustained by contemporary medicine
Cryoprecipitate, a blood-derived protein product used to treat some bleeding disorders
Cryotherapy, medical treatment using cold
Cryoablation, tissue removal using cold
Cryosurgery, surgery using cold
Cryo-electron microscopy (cryoEM), a technique that fires beams of electrons at proteins that have been frozen in solution, to deduce the biomolecules’ structure

Other uses
Cryo Interactive, a video game company
Cryos, a planet in the video game Darkspore

See also
All pages with titles beginning with Cryo
Kryo, a brand of CPUs by Qualcomm

External links
 The dictionary definition of cryo- at Wiktionary