The Collaborative International Dictionary of English v.0.48:

Calvin \Cal"vin\ n.
   1. John Calvin, a French theologian and reformer; born 1509,
      died 1564.
      [WordNet 1.5]

WordNet (r) 3.0 (2006):

Calvin
    n 1: United States chemist noted for discovering the series of
         chemical reactions in photosynthesis (1911-) [syn:
         Calvin, Melvin Calvin]
    2: Swiss theologian (born in France) whose tenets
       (predestination and the irresistibility of grace and
       justification by faith) defined Presbyterianism (1509-1564)
       [syn: Calvin, John Calvin, Jean Cauvin, Jean Caulvin,
       Jean Chauvin]