hypoparathyroidism Syllabification: (hy·po·par·a·thy·roid·ism)Pronunciation: /ˌhīpōˌparəˈTHīroiˌdizəm/Definition of hypoparathyroidism noun Medicine diminished concentration of parathyroid hormone in the blood, which causes deficiencies of calcium and phosphorus compounds in the blood and results in muscular spasms. Derivatives hypoparathyroid adjective hypoparathyroidism in other Oxford dictionaries Definition of hypoparathyroidism in the British & World English dictionary