What does rainwater mean?
Rainwater is water that falls as rain, including rain falling during a storm and water collected from roofs, gutters, or other surfaces. The term commonly appears in discussions of household water conservation, agriculture, landscaping, and building design, especially in relation to collecting and storing rainwater for later use. As a mass noun, it normally takes a singular article, as in “the rainwater,” and does not commonly have a plural form in everyday usage. “Rainfall” can sometimes be used in a related sense, but it more precisely denotes the quantity of precipitation rather than the water itself. Rainwater is also distinct from “stormwater,” which may include runoff from melting snow, sewer overflows, and other urban drainage flows in addition to direct rainfall.
nounWater that falls as rain, especially when collected or used for practical purposes. It may also refer generally to precipitation in the form of rain.
- Water that falls as rain or has been collected from rain.
"The roof collects rainwater in a large tank for use in the garden."
"After the storm, rainwater ran along the gutters and into the drain."
"Installing a rainwater system can reduce household demand for treated mains water."
Rare and usually used when referring to separate bodies or supplies of rainwater, particularly in technical contexts.
"The report compares rainwaters collected from different parts of the city."
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does rainwater come from?
The compound dates from the early modern period and is formed straightforwardly from the English words “rain” and “water.” “Rain” descends from Old English regn, while “water” comes from Old English wæter, both Germanic words with cognates in other Germanic languages. The compound was initially associated with water falling from rain and later became especially common for water collected from roofs and similar surfaces.
How rainwater is actually used
Usually used as a singular mass noun. The plural form is uncommon, although it can refer to separate bodies or supplies of rainwater, especially in technical or environmental contexts.
Easily confused with rainwater
Rainfall is the amount of rain that falls in an area or during a period, whereas rainwater refers to the water itself, particularly when collected or reused.