Oxford Advanced American Dictionary

Definition of rain verb from the Oxford Advanced Learner's Dictionary

 Oxford3000

rain

verb
rain pronunciation English reɪn rain pronunciation American reɪn
 
1 [intransitive] when it rains, water falls from the sky in dropsIs it raining?It had been raining hard all night.It hardly rained at all last summer.It started to rain.2 [intransitive, transitive] to fall or to make something fall on somebody/something in large quantitiesrain (down) (on somebody/something) Bombs rained (down) on the city's streets.Falling debris rained on us from above.He covered his face as the blows rained down on him (= he was hit repeatedly).rain something (down) (on somebody/something) The volcano erupted, raining hot ash over a wide area.
Idioms

be raining cats and dogs

(informal) to be raining heavily

it never rains but it pours

(British English) (North American English when it rains, it pours) (saying) used to say that when one bad thing happens to you, other bad things happen soon after

rain on somebody's parade

(North American English, informal) to spoil something for somebody
Phrasal verbs

be rained off

(British English) (North American English be rained out) (of an event) to be cancelled or to have to stop because it is rainingThe game has been rained off again.