The Collaborative International Dictionary of English v.0.48:
ergocalciferol \ergocalciferol\ n. vitamin D2, one of the D vitamins, a group of related substances that prevent rickets. Syn: vitamin D, calciferol, cholecarciferol, D. [WordNet 1.5 +PJC]WordNet (r) 3.0 (2006):
ergocalciferol n 1: a fat-soluble vitamin that prevents rickets [syn: vitamin D, calciferol, viosterol, ergocalciferol, cholecalciferol, D]