From Longman Dictionary of Contemporary Englishrazorra‧zor /ˈreɪzə $ -ər/ ●○○ noun 1 
DCB[countable] a tool with a sharp blade, used to remove hair from your skin → shaver an electric razor a disposable razor2 → be on a razor/razor’s edge
DCB[countable] a tool with a sharp blade, used to remove hair from your skin → shaver an electric razor a disposable razor2 → be on a razor/razor’s edgeExamples from the Corpus
razor• His hairbrush, razor, everything I'd previously touched, had relinquished his identity.• An open razor, the blade thick with clotted blood lay on top of it, a few inches from his right hand.• He stopped freezing his wrist long enough to prop a clean blade against the razor case.• My hands shook as I slowly ran the razor over my face, cutting through the cream in even swaths.Origin razor (1200-1300) Old French raseor, from raser; → RAZE 