The Collaborative International Dictionary of English v.0.48:
Criminology \Crim`i*nol"o*gy\ (-n?l"?-j?), n. [L. crimen, crimenis, crime + -logy.] 1. A treatise on crime or the criminal population. [1913 Webster] 2. The branch of sociology which studies crime and criminals. [PJC] -- Crim`i*nol"o*gist (-j?st), n. [1913 Webster]WordNet (r) 3.0 (2006):
criminologist n 1: a specialist in criminology