pluviometer
/ˌpluːvɪˈɒmɪtə/noun
An instrument for measuring rainfall; a rain gauge.
Origin
Mid 18th century; earliest use found in Benjamin Martin (bap. 1705, d. 1782), lecturer on science and maker of scientific instruments. From classical Latin pluvia rain + -meter. In form pluviometer probably after French pluviomètre; compare -ometer.