Caffeine

2 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  caffein \caf*fe"in\, Caffeine \Caf*fe"ine\, n. [Cf. F.
     caf['e]ine. See {Coffee}.] (Chem.)
     A white, bitter, crystallizable substance, found in coffee
     and tea. It is identical with the alkaloid {theine} from tea
     leaves, and with {guaranine} from guarana. It is responsible
     for most of the stimulating effect of coffee or tea.


     [1913 Webster + WordNet 1.5]

From WordNet (r) 2.0 [wn]:

  caffeine
       n : a bitter alkaloid found in coffee and tea that is
           responsible for their stimulating effects [syn: {caffein}]