'Knife-edge' definitions:
Definition of 'knife-edge'
From: WordNet
noun
A narrow boundary; "he lived on a knife-edge between genius and insanity"
Definition of 'Knife-edge'
From: GCIDE
- Knife-edge \Knife"-edge`\, n. (Mech.) 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. [1913 Webster]
- Knife-edge file. See Illust. of File. [1913 Webster]