master key

American  

noun

1. a key that will open a number of different locks, the proper keys of which are not interchangeable.

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master key British  

noun

1. Also called: pass key.  a key that opens all the locks of a set, the individual keys of which are not interchangeable

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Etymology

Origin of master key

First recorded in 1570–80

Example Sentences

"The attacker effectively gains a 'master key' to your digital identity," said the engineer, who has named his OpenClaw agent "Q" after his business name QLab.

From Barron's

Antibodies can sometimes act like a master key, helping trigger immune responses.

From Science Daily

At 15:19, she tried the door to the toilet, using a master key to unlock it.

From BBC

Staff had master keys that could unlock all the patients' rooms.

From BBC

"As we have said many times before, we have never built a backdoor or master key to any of our products or services and we never will."

From BBC