Source : Webster's Revised Unabridged Dictionary (1913)

Centralization \Cen`tral*i*za"tion\, n. [Cf. F. centralisation.]
   The act or process of centralizing, or the state of being
   centralized; the act or process of combining or reducing
   several parts into a whole; as, the centralization of power
   in the general government; the centralization of commerce in
   a city.

Source : WordNet®

centralization
     n 1: the act of consolidating power under a central control [syn:
           {centralisation}] [ant: {decentralization}]
     2: gathering to a center [syn: {centralisation}]