Source : Webster's Revised Unabridged Dictionary (1913)

Proliferation \Pro*lif`er*a"tion\, n.
   1. (Biol.) The continuous development of cells in tissue
      formation; cell formation. --Virchow.

   2. (Zo["o]l.) The production of numerous zooids by budding,
      especially when buds arise from other buds in succession.

Source : WordNet®

proliferation
     n 1: growth by the rapid multiplication of parts
     2: a rapid increase in number (especially a rapid increase in
        the number of deadly weapons); "the proliferation of
        nuclear weapons" [ant: {nonproliferation}, {nonproliferation}]