Air conditioning; cooling function or system used to lower indoor temperature (e.g., air conditioning).
夏は冷房がないと過ごせない。
I can't get through summer without air conditioning.
冷房が効きすぎて少し寒い。
The air conditioning is too strong and it's a bit cold.
電車の中は冷房が強かった。
The air conditioning on the train was strong.