The Collaborative International Dictionary
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.
Knife-edge file. See Illust. of File.
Wiktionary
alt. 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 (context figuratively English) A precarious balance that could be upset by a very small force in either direction. 3 (&lit the edge of a knife English) n. 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 (context figuratively English) A precarious balance that could be upset by a very small force in either direction. 3 (&lit the edge of a knife English)
WordNet
n. a narrow boundary; "he lived on a knife-edge between genius and insanity"
Wikipedia
"Knife-Edge" is a song by the British progressive rock group Emerson, Lake & Palmer. It is the third track of their eponymous debut album. The song is based on the first movement of Leoš Janáček's Sinfonietta (1926) with an instrumental middle section that includes an extended quotation from the Allemande of Johann Sebastian Bach's first French Suite in D minor, BWV 812, but played on an organ rather than clavichord or piano. Like the song " The Barbarian" on the same album, "Knife-Edge" was also not credited to its original composer. Janáček's family sued ELP for copyright infringement, but eventually the credit to Janáček was added, too. The song was released as a B-side to ELP's single " Lucky Man", also from the debut album. The song was a popular concert staple and has appeared on nearly every ELP compilation album. In May 2012, Steven Wilson of Porcupine Tree remixed the debut album for a 3-CD reissue containing the original mix, the Wilson remix, and a DVD-Audio with Wilson's 5.1 surround sound version and a higher bit-rate version of his stereo mix. Wilson's remix of "Knife-Edge" has an extended ending; due to the difficulty of reproducing the song's original tape slowdown ending digitally, Wilson chose instead to include the end of the original album session at its original speed.
Usage examples of "knife-edge".
Golan Trevize -the First Foundationer who has been driven from Terminus and whom the First Speaker and I believe to be the knife-edge of the gathering crisis has moved off in an unexpected direction.
We met the equivalent of this knife-edge, you will remember, in the story of the Grudgers and Cheats in Chapter 10.
He tapped a shot of Isobelle Patissier seven hundred feet up some knife-edge arete in Colorado.
Did a little knife-edge snowboarding, avalanche racing, stuff like that.
His broad shoulders and narrow waist were accentuated by his understated but exceedingly well-cut ankle-length suit coat and knife-edge dress slacks.
The rod being held parallel to the axis of the bore, with the side of the head pressing the rimbase, the knife-edge will be in a proper position to fall into the base line when moved to find it.
He was wearing combat fatigues, clean, with knife-edge creases, a blue beret sporting a single silver star.
He is aware of the knife-edge chemical balance between animation and dead jelly, with its roots in order, hierarchy, interaction.
There were striations of ivory and blue, knife-edges of brass, glints of jade green, saffron, cocoa brown.
He found a spiritual knife-edge in the poetry of alien places, where extreme situations become inevitable and characters are forced toward life-defining moments.
No human could maintain the knife-edge tolerances needed for a hypersonic lifting aeropass, and so the guidance computer, with its crystalline logic and perfect mathematical calculations, had done the flying, comparing the predictions of the computer model with the performance of the actual vehicle a thousand times a second, adjusting in real time for variations in exospheric density and discrepancies between the computer model and the actual vehicle.
It took us only four and a half days to get down, and that included a day of rest at our old Camp Three on the low side of the knife-edge traverse.
Kincar was by the window again, studying his knife-edge view of the city, when the outer bar of the door was drawn.
Can we not understand that it was needful to shake mankind loose from gossip and pink teas, and sword-worship, and Saturday night drunks, and self seeking politics and theological quibbles -- to wake them up and make them realise that they stand upon a narrow knife-edge between two awful eternities, and that, here and now, they have to finish with make-beliefs, and with real earnestness and courage face those truths which have always been palpable where indolence, or cowardice, or vested interests have not obscured the vision.