if it rains, drops of water fall from clouds in the sky:
Outside it was still raining.
It's starting to rain.
It must have rained quite hard last night.
it's raining cats and dogs spoken (=it is raining very hard)
if you rain blows onto someone, you hit them many times:
She attacked the man, raining blows on his head and shoulders.
used to say that as soon as one thing goes wrong, a lot of other things go wrong as well
rain downphrasal verb
rain down on
Bombs rained down on the city.
be rained offphrasal verb
if an event or activity is rained off or rained out, it has to stop because there is too much rain:
The match was rained off.