The Collaborative International Dictionary of English v.0.48:

Binuclear \Bi*nu"cle*ar\, Binucleate \Bi*nu"cle*ate\, a. [Pref.
   bi- + nuclear, nucleate.] (Biol.)
   Having two nuclei; as, binucleate cells.
   [1913 Webster]

WordNet (r) 3.0 (2006):

binuclear
    adj 1: having two nuclei [syn: binucleate, binuclear,
           binucleated] [ant: mononuclear, mononucleate,
           trinuclear, trinucleate, trinucleated]