Technical term for a substance used in refrigeration or cooling systems. Both 'refrigerant' and 'coolant' are valid translations, with 'refrigerant' more specific to phase-change cooling.
エアコンには冷媒としてフロンガスが使われている。
Freon gas is used as a refrigerant in air conditioners.
Please check for refrigerant leaks.
Compound of 冷 (rei, 'cold') and 媒 (bai, 'medium, intermediary'). The exact historical derivation is uncertain, but the word follows standard Sino-Japanese word formation patterns.