master key

noun

plural master keys

1

a

: a key designed to open any of a set of similar locks (as on the doors of a building)

The porter unlocked the door with his master key.

—Paul Wilkinson

… he borrowed the electronic master key …—a fob which unlocks all the bedrooms in the building—and used it to enter another resident's room.

—Jason Evans

… the … idea of coordinating luggage inspection by providing locks that the TSA can open with a master key.

—Ryan Davis

called also passkey

b

: something (such as a set of computer instructions or a specific sequence of characters) that provides digital access to a variety of systems, files, etc.

… an alarmingly powerful cipher … that could be used as a master key to bypass basically any security system imaginable …

—Sara Netzley

The cybercriminals behind the … ransomware have decided to close up shop and have now released the master key capable of decrypting files locked with their malware.

—Anthony Spadafora

You can store all your passwords in one database, which is locked with a master key. So you only have to remember one single master key to unlock the whole database.

—TechSpot.com

2

: a crucial means of understanding or attaining something

—usually used with to

That's when it clicked. I had trained my mind to think what I wanted. At that point, I knew mindset training was the master key to success.

—David DeRam

One approach to defeating aging suggests replacing body parts as they fail. Another aims at finding a master key to youth.

—Todd Friend

… a man I thought might hold the master key to one of the strangest scholarly mysteries in recent decades …

—Ariel Sabar

Examples of master key in a Sentence

Recent Examples on the Web

The robber unlocks the office safe, which contains a master key. —Renee Dudley, ProPublica, 13 June 2024

That was extraordinary to us and really leads us toward this idea that these drugs might be master keys for unlocking lots of critical periods. —Quanta Magazine, 6 June 2024

The mail carrier, identified as T.W. in court documents, reported to authorities that the robbers demanded a USPS arrow key, also known as a master key, at gunpoint on Oct. 2, 2023, according to the release. —Nicole Lopez, Fort Worth Star-Telegram, 15 May 2024

About a year and a half ago, United States Postal Service Inspector Jeff Fitch said, thieves were able to get a hold of a master key. —Angela Rodriguez, Sacramento Bee, 15 Apr. 2024

Word History

First Known Use

1577, in the meaning defined at sense 1