calcitoninPronunciation: /ˌkalsɪˈtəʊnɪn/Definition of calcitonin noun [mass noun] Biochemistry a hormone secreted by the thyroid that has the effect of lowering blood calcium. Origin: 1960s: from calci- + tonic + -in1calcitonin in other Oxford dictionaries Definition of calcitonin in the US English dictionary
