The Collaborative International Dictionary of English v.0.48:

Dialyze \Di"a*lyze\, v. t. [imp. & p. p. Dialyzed; p. pr. &
   vb. n. Dialyzing.] (Chem.)
   To separate, prepare, or obtain, by dialysis or osmose; to
   pass through an animal membrane; to subject to dialysis.
   [Written also dialyse.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

dialyse
    v 1: separate by dialysis [syn: dialyse, dialyze]