What's the difference between i.e. and e.g.?
1896, from Greek proktos "anus," from PIE *prokto- + -logy "study of." Related: Proctologist (1897).
proctology proc·tol·o·gy (prŏk-tŏl'ə-jē)n. The branch of medicine that deals with the diagnosis and treatment of disorders of the colon, rectum, and anus.