<P> A skeleton key (also known as a passkey) is a type of master key in which the serrated edge has been filed down so that it can open numerous locks, most commonly the warded lock . The term derives from the fact that the key has been reduced to its essential parts . </P> <P> In a broader sense the term can be used synonymously with master key to refer to any key, keycard or other device capable of opening a variety of locks . </P>

Why is a skeleton key called a skeleton key
find me the text answering this question