knife-edge

Noun

 * 1) 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.
 * 2)  A precarious balance that could be upset by a very small force in either direction.

Derived terms

 * knife-edge effect
 * knife-edge effect

Translations

 * Finnish:
 * French: fil du rasoir
 * German: Messers Schneide
 * Italian: filo del rasoio
 * Polish: ostrze noża
 * Russian: ле́звие ножа́
 * Turkish: