A cloud from which rain is falling or may fall.

(idiomatic) to rain heavily.

(Australia, Canada, India, New Zealand, UK) rain check

plural of rain man

(idiomatic) Any voucher or note from a merchant to a customer to provide an item the merchant has run out of at a later date for the item's current price, or (in a more literal sense) to provide a service at a later date.

(simile, colloquial) Very good; all in order; healthy. / (simile, colloquial) Correct; factually accurate.

A device used in meteorology to measure rainfall; a pluviometer.

(idiomatic) Regardless of what the circumstances are, and how the weather is.

The yellow-billed cuckoo (Coccyzus americanus)

rain contaminated by fungi spores, soot, or other particulate matter / radioactive rain that fell on Hiroshima following the atomic bombing of 1945