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