rain noun definition in Rain topic from the Oxford Advanced Learner's Dictionary

rain

 noun: Rain topic
[uncountable, singular] water that falls from the sky in separate drops There will be rain in all parts tomorrow. Rain is forecast for the weekend. Don't go out in the rain. It's pouring with rain (= raining very hard). heavy/torrential/driving rain The rain poured down. It looks like rain (= as if it is going to rain). A light rain began to fall. I think I felt a drop of rain.