The Collaborative International Dictionary of English v.0.48:

initialize \initialize\ v. t.
   to assign an initial value to (a variable or set of variables
   in a computer program); as, many bugs are caused by a failure
   to initialize variables.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

initialize
    v 1: assign an initial value to a computer program [syn:
         initialize, initialise]
    2: divide (a disk) into marked sectors so that it may store
       data; "Please format this disk before entering data!" [syn:
       format, initialize, initialise]