one of the commonest minerals, calcium carbonate, CaCO 3 , found in a great variety of crystalline forms: a major constituent of limestone, marble, and chalk; calc-spar. Historical Examples Encyclopaedia Britannica, 11th Edition, Volume 4, Part 4 Various De Re Metallica Georgius Agricola The Voyage of the Vega round Asia and Europe, Volume I and […]
a polypeptide hormone that participates in the regulation of calcium levels in vertebrates by inhibiting loss of calcium from bone to the blood. noun a hormone secreted by the thyroid that inhibits the release of calcium from the skeleton and prevents a build-up of calcium in the blood Also called thyrocalcitonin Compare parathyroid hormone calcitonin […]
Biochemistry. a vitamin D compound, C 27 H 44 O 3 , occurring in humans as a hormone derived from cholesterol, that acts in the regulation and absorption of calcium. Pharmacology. a preparation of this compound, used in the treatment of osteoporosis and bone fracture.