Source : Webster's Revised Unabridged Dictionary (1913)

Centrality \Cen*tral"i*ty\, n.; pl. {Centralities}.
   The state of being central; tendency towards a center.

         Meantime there is a great centrality, a centripetence
         equal to the centrifugence.              --R. W.
                                                  Emerson.

Source : WordNet®

centrality
     n : the property of being central [ant: {marginality}]