The Collaborative International Dictionary of English v.0.48:

operationalism \operationalism\ n. (Philos.)
   the doctrine that the meaning of a proposition consists of
   the operations involved in defining, proving, or applying it.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

operationalism
    n 1: (philosophy) the doctrine that the meaning of a proposition
         consists of the operations involved in proving or applying
         it