Definify.com
Webster 1913 Edition
Knife-edge
Knife′-edgeˊ
,Noun.
(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.
Knife-edge file
. See Illust. of
File
.