CISTERN Meaning of CISTERN in English ■ noun1》 a water storage tank, especially as part of a flushing toilet. 2》 an underground reservoir for rainwater.OriginME: from OFr. ~e , from L. ~a , from cista (see cist 2 ). Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004