1. (n.)-logy a combiningformmeaning “field of scientific study, discipline,” used also to denote the body of principles, theories, data, etc., produced by learned endeavor ( archaeology; pathology; theology; ); “set of abstract notions” (; ideology; methodology; ); “set of texts” (; trilogy; ); “systematic listing” (; genealogy; necrology; ); “linguistic usage” (tautology; phraseology).
Etymology: (ME -logie < L -logia < Gk. See -logue , -y3)
Definition of '-logy'
Webster Dictionary
1. -logy a combiningform denoting a discourse, treatise, doctrine, theory, science; as, theology, geology, biology, mineralogy
Definitions of -logy 
