RENIN Meaning of RENIN in English [ 'ri:nɪn ]■ noun Biochemistry an enzyme secreted by and stored in the kidneys which promotes the production of the protein angiotensin.OriginC19: from L. ren 'kidney' + -in 1 . Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004