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

Nevertheless, an employee used a master key to enter the room and leave Payne there. —Martha Ross, The Mercury News, 26 Nov. 2024

The workers then opened the room door with a master key and put Liam inside. —Vivian Kwarm, New York Daily News, 25 Nov. 2024

Twitter and Facebook, in an effort to put themselves at the center of Internet users’ online activity, allow their login credentials to be used as a kind of master key for granting access to third-party apps. —IEEE Spectrum, 25 Jan. 2013

Advertisement The lawsuit alleges that the Los Angeles County Sheriff’s Department did not have access to the master key lock and no staff was present to open the door for deputies, which delayed the arrest of Nguyen. —Ruben Vives, Los Angeles Times, 16 Oct. 2024

Word History

First Known Use

1577, in the meaning defined at sense 1