• enPR: rān, IPA: /ɹeɪn/

rain (uncountable)

1. Condensed water falling from a cloud.

   We've been having a lot of rain lately.

   The rains came late that year.

   • 2019, [https://web.archive.org/web/20190311070055/https://learningenglish.voanews.com/a/south-korea-proposes-rain-project-with-china-to-cut-pollution/4819207.html VOA Learning English] (public domain)

     This process involves cloud seeding – when various substances are put into clouds in an attempt to cause rain.

2. (figuratively) Any matter moving or falling, usually through air, and especially if liquid or otherwise figuratively identifiable with raindrops.
3. (figuratively) An instance of particles or larger pieces of matter moving or falling through air.

   A rain of mortar fire fell on our trenches.

• See also Thesaurus:hydrometeor

rain (rains, present participle raining; past and past participle rained)

1. (impersonal) To have rain fall from the sky.

   It will rain today.

2. (intransitive) To fall as or like rain.

   It will rain fire and brimstone at the end of days.

   • c. 1601–1602, William Shakespeare, “Twelfe Night, or VVhat You VVill”, in Mr. William Shakespeares Comedies, Histories, & Tragedies: Published According to the True Originall Copies (First Folio), London: Printed by Isaac Iaggard, and Ed[ward] Blount, published 1623, OCLC 606515358 ↗, [Act V, scene i]:

     The rain it raineth every day.

   Tears rained from her eyes.

   Leaves rained from the tree.

   Bombs rained from the sky.

3. (transitive) To issue (something) in large quantities.

   The boxer rained punches on his opponent's head.

4. (obsolete) To reign.
   • , Edmund Spenser, Faerie Queene, Book I, canto V

     Such wondrous science in mans witt to rain.