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fail-safe

[feyl-seyf] /ˈfeɪlˌseɪf/
adjective
1.
Electronics. pertaining to or noting a mechanism built into a system, as in an early warning system or a nuclear reactor, for insuring safety should the system fail to operate properly.
2.
equipped with a secondary system that insures continued operation even if the primary system fails.
3.
(sometimes initial capital letter) of, pertaining to, or designating a system of coded military controls in which bombers dispatched to a prearranged point as part of a standard operating procedure cannot advance farther without direct orders from a designated authority and cannot have the nuclear warheads they carry armed until they have passed their prearranged point.
4.
guaranteed to work; totally reliable:
a fail-safe recipe for a cheese soufflé.
noun
5.
(sometimes initial capital letter) the point beyond which the bombers cannot go without specific instruction; the fail-safe point.
6.
something designed to work or function automatically to prevent breakdown of a mechanism, system, or the like.
verb (used with object), fail-safed, fail-safing.
7.
to make fail-safe.
Origin
1945-1950
1945-50; apparently from verb phrase to fail safe(ly)
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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British Dictionary definitions for failsafe

fail-safe

adjective
1.
designed to return to a safe condition in the event of a failure or malfunction
2.
(of a nuclear weapon) capable of being deactivated in the event of a failure or accident
3.
unlikely to fail; foolproof
verb
4.
(intransitive) to return to a safe condition in the event of a failure or malfunction
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for failsafe
adj.

also fail-safe, fail safe "safe against failure," 1948, from fail (v.) + safe (adj.). Earliest reference is to furnace burners.

Online Etymology Dictionary, © 2010 Douglas Harper
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