Source : Webster's Revised Unabridged Dictionary (1913)

Aberrance \Ab*er"rance\, Aberrancy \Ab*er"ran*cy\, n.
   State of being aberrant; a wandering from the right way;
   deviation from truth, rectitude, etc.

   {Aberrancy of curvature} (Geom.), the deviation of a curve
      from a circular form.

Source : WordNet®

aberrancy
     n : a state or condition markedly different from the norm [syn:
         {aberrance}, {aberration}, {deviance}]