1911 Encyclopædia Britannica/Rain
RAIN (O.E. regn; the word is common to Teutonic languages, cf. Ger. Regen, Swed. and Dan. regn; it has been connected with Lat. rigare, to wet, Gr. βρέχειν), the water vapour of the atmosphere when condensed into drops large enough to be precipitated upon the earth. Hence the term is extended to signify the fall of such drops in a shower, and in the plural, “the rains,” it signifies the rainy seasons in India and elsewhere where under normal climatic conditions such seasons are clearly distinguished from the dry. A rain-band is “a dark band in the solar spectrum, caused by the presence of water-vapour in the atmosphere” (New Engl. Dict.); a rain-gauge is an instrument used to measure the amount of rainfall (see Meteorology, where the whole subject of precipitation is fully treated).