The Collaborative International Dictionary of English v.0.48:
vitamin B12 \vitamin B12\ n. a B vitamin that is used to treat pernicious anemia. Syn: cobalamin, cyanocobalamin. [WordNet 1.5]WordNet (r) 3.0 (2006):
vitamin B12 n 1: a B vitamin that is used to treat pernicious anemia [syn: vitamin B12, cobalamin, cyanocobalamin, antipernicious anemia factor]