vasopressinPronunciation: /ˌveɪzəʊˈprɛsɪn/Definition of vasopressin noun [mass noun] Biochemistry a pituitary hormone which acts to promote the retention of water by the kidneys and increase blood pressure. Origin: 1920s: blend of vasopressor and -in1vasopressin in other Oxford dictionaries Definition of vasopressin in the US English dictionary
