Source : Webster's Revised Unabridged Dictionary (1913)

Penology \Pe*nol"o*gy\, n. [Gr. ?, or L. poena, punishment +
   -logy.]
   The science or art of punishment. [Written also
   {p[oe]nology}.]

Source : WordNet®

penology
     n : the branch of criminology concerned with prison management
         and prisoner rehabilitation [syn: {poenology}]