The Collaborative International Dictionary of English v.0.48:

centralizing \centralizing\ adj. prenom.
   causing to concentrate at a center. Opposite of
   decentralizing. [Narrower terms: centripetal,
   unifying(prenominal)]
   [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Centralize \Cen"tral*ize\, v. t. [imp. & p. p. Centralized; p.
   pr. & vb. n. Centralizing.] [Cf. F. centraliser.]
   To draw or bring to a center point; to gather into or about a
   center; to bring into one system, or under one control.
   [1913 Webster]

         [To] centralize the power of government. --Bancroft.
   [1913 Webster]

WordNet (r) 3.0 (2006):

centralizing
    adj 1: tending to draw to a central point [syn:
           centralizing(a), centralising(a)] [ant:
           decentralising(a), decentralizing(a)]