The Collaborative International Dictionary of English v.0.48:

Adessenarian \Ad*es`se*na"ri*an\, n. [Formed fr. L. adesse to be
   present; ad + esse to be.] (Eccl. Hist.)
   One who held the real presence of Christ's body in the
   eucharist, but not by transubstantiation.
   [1913 Webster]