- 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.
- equipped with a secondary system that insures continued operation even if the primary system fails.
- (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.
- guaranteed to work; totally reliable: a fail-safe recipe for a cheese soufflé.
- (sometimes initial capital letter) the point beyond which the bombers cannot go without specific instruction; the fail-safe point.
- something designed to work or function automatically to prevent breakdown of a mechanism, system, or the like.
verb (used with object), fail-safed, fail-saf·ing.
- to make fail-safe.
- designed to return to a safe condition in the event of a failure or malfunction
- (of a nuclear weapon) capable of being deactivated in the event of a failure or accident
- unlikely to fail; foolproof
- (intr) to return to a safe condition in the event of a failure or malfunction