1) Refrigerant 2) Requiring low temperatures 
Temperature at which gases liquefy at atmospheric pressure.
A rocket fuel or oxidizer which is liquid only at very low temperatures, e.g. liquid hydrogen which has a boiling point of -217.2oC (-423oF).
Empire Magnetics cryogenic motors and related products are rated for an ambient temperature of 20¢X K though motors rated for an ambient temperature of 4¢X K have been provided on a custom basis.
<radiobiology> Loosely, very cold. Used to describe systems at very low temperatures. ... Superconducting magnetic field coils currently need to operate at cryogenic temperatures (for example, liquid helium at 4 Kelvin). ... Origin: Gr. Gennan = to produce ... (09 Oct 1997) ... 
(kri″o-jen´ik) producing low temperatures.
Extremely cold freezing process, using liquid nitrogen or carbon dioxide, often used to freeze high-value items like shrimp or soft-shell crabs.
Type: Term Pronunciation: krī′ō-jen′ik Definitions: 1. Denoting or characteristic of a cryogen. 2. Relating to cryogenics.
[adj] - of or relating to very low temperatures
cryogenic 1. Pertaining to or causing the production of low temperatures. 2. Relating to cryogenics. 3. Cryogenic lake, a lake formed by local thawing in an area of permanently frozen ground.
Pertaining to very low temperature. Aluminum gains strength as temperature is reduced, making it an appropriate material for cryogenic applications
adjective of or relating to very low temperatures
Very cold temperatures.
of or pertaining to the production or use of very low temperatures: cryogenic storage. · of or pertaining to cryogenics.