The Collaborative International Dictionary of English v.0.48:

Utraquist \U"tra*quist\, n. [L. uterque, fem. utraque, both.]
   One who receives the eucharist in both kinds; esp., one of a
   body of Hussites who in the 15th century fought for the right
   to do this. Called also Calixtines.
   [1913 Webster]