knife-edge
noun
Forms knife-edges knife edge knife's edge knife's-edge
- noun (mechanics) A small piece of metal, usually steel, sharpened to an acute edge or angle, and resting on a smooth surface, serving as the fulcrum of a pendulum, scalebeam, or other piece required to oscillate with minimal friction.
- noun (figuratively) A precarious balance that could be upset by a very small force in either direction. “The game was on a knife-edge.”
- noun Used other than figuratively or idiomatically: the edge of a knife.
Webster’s 1913
- noun A piece of steel sharpened to an acute edge or angle, and resting on a smooth surface, serving as the axis of motion of a pendulum, scale beam, or other piece required to oscillate with the least possible friction. Knife-edge file. See Illust. of File.
- noun A switch consisting of one or more knifelike pieces hinged at one end and making contact near the other with flat gripping springs.
Sources: Wiktionary · Webster’s 1913 — from the Wiktionary entry “knife-edge”, CC BY-SA 4.0. Details