The Collaborative International Dictionary of English v.0.48:

Crocin \Cro"cin\ (kr?"s?n), n. [Gr. ???? saffron.] (Chem.)
   (a) The coloring matter of Chinese yellow pods, the fruit of
       Gardenia grandiflora. --Watts.
   (b) A red powder (called also polychroite), which is made
       from the saffron (Crocus sativus). See Polychroite.
       [1913 Webster]