What's the definition of a master key?

What makes a key a master key?

Any key that can open two or more locks is considered a master key. Many master keys use pin and tumbler locks. For a master key to work, though, there must be something called master wafers inside the lock. When the master wafers line up, the key and lock can turn freely.

What is the difference between a master key and a regular key?

Some locks are designed to work with two different keys. The change key will open only that specific lock, while the master key will open that lock and several others in a group.

How do I know if I have a master key?

"Master keys are identified with a simple test. You can test whether or not you have a Master key by watching the Security light as you insert your key into the ignition. If the Security light turns off immediately after insertion of the key, it is a Master key.

Can a master key open any lock?

A master key is a key capable of operating several different locks, each lock being operated by its own separate key (change key). Many people think that they have a master key because they have one key which operates many locks in their home.