Early 19th century; earliest use found in The Morning Chronicle. From classical Latin perpetrāt-, past participial stem of perpetrāreperpetrate + -trix, after perpetrator.
Definition of perpetratrix in US English:
perpetratrix
nounˈpəːpɪˌtreɪtrɪks
= perpetratress.
Origin
Early 19th century; earliest use found in The Morning Chronicle. From classical Latin perpetrāt-, past participial stem of perpetrāre perpetrate + -trix, after perpetrator.