noun (n)

• the act of consolidating power under a central control(noun.act)

  Synonym:
  centralisation
  Antonym:
  decentralisation, decentralization
  

  source: wordnet30
• gathering to a center(noun.act)

  source: wordnet30
• 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.(noun)

  source: webster1913