The Collaborative International Dictionary of English v.0.48:

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

   Syn: aberrance, aberration, deviance
        [1913 Webster WordNet 1.5]

   Aberrancy of curvature (Geom.), the deviation of a curve
      from a circular form.
      [1913 Webster]

WordNet (r) 3.0 (2006):

aberrance
    n 1: a state or condition markedly different from the norm [syn:
         aberrance, aberrancy, aberration, deviance]