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fail-safe

[feyl-seyf]
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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, relating 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.
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noun
  1. (sometimes initial capital letter) the point beyond which the bombers cannot go without specific instruction; the fail-safe point.
  2. something designed to work or function automatically to prevent breakdown of a mechanism, system, or the like.
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verb (used with object), fail-safed, fail-saf·ing.
  1. to make fail-safe.
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Origin of fail-safe

First recorded in 1945–50; apparently from verb phrase to fail safe(ly)
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words

soundconfidentfoolproofprotectedreliablesecuresurereliant

Examples from the Web for fail-safe

Contemporary Examples

Historical Examples

  • Internally, the communications beam to Thule Base had been interrupted; and the fail-safe had not failed-safely.


British Dictionary definitions for fail-safe

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
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verb
  1. (intr) to return to a safe condition in the event of a failure or malfunction
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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