Source : Webster's Revised Unabridged Dictionary (1913)

Criminology \Crim`i*nol"o*gy\ (-n?l"?-j?), n. [L. crimen,
   crimenis, crime + -logy.]
   A treatise on crime or the criminal population. --
   {Crim`i*nol"o*gist} (-j?st), n.

Source : WordNet®

criminologist
     n : a specialist in criminology