Source : Webster's Revised Unabridged Dictionary (1913)

Convergence \Con*ver"gence\, Convergency \Con*ver"gen*cy\, n.
   [Cf. F. convergence.]
   The condition or quality of converging; tendency to one
   point.

         The convergence or divergence of the rays falling on
         the pupil.                               --Berkeley.

Source : WordNet®

convergency
     n 1: the approach of an infinite series to a finite limit [syn: {convergence}]
          [ant: {divergence}, {divergence}]
     2: the act of converging (coming closer) [syn: {convergence}, {converging}]