Definition from Wiktionary, the free dictionary
From Middle English reinwater, from Old English reġnwæter (“rainwater”), equivalent to rain + water. Cognate with Dutch regenwater (“rainwater”), German Regenwasser (“rainwater”), Swedish regnvatten (“rainwater”).
- Water (for a house etc) sourced from rain which has not joined a spring, stream or river, pond, lake or sea.
rainfall — see rainfall