0 a key that can be used to open any of several different locks --
1 a key that can be used to open a number of different locks --
Its products are typically marketed toward and installed into moderately sized or larger master key systems.
And even now they can be understood only by those who possess the master key to unlock them.
It seems to me that it is technical and professional training which is the master key for solving the terrible problem of dealing with disabled officers and men.
He may be worried that persons could be forced to hand over a master key rather than, say, a session key because the authority serving the notice provided insufficient information.
For all that work his master key was the revenue provided by the mining industry, and, secondly, as an essential temporary measure, a substantial loan of £6,000,000 or £7,000,000 for reconstruction.
Drastic arms reductions are the master key to the problems facing our country.
Common ownership of a new town's estate was often referred to by him as the "master key".
Each member has one of these small safes, numbered, but he has not a key, the master key being kept by the secretary or treasurer.