Key (lock)

A key is a device which is used to open a lock by turning. They consist of two parts, the blade, which is inserted into the lock, and the bow, left protruding so that a torque can be applied. The blade of a key is normally designed to open one specific lock, although master keys are designed to open sets of similar locks.

Keys are an essential feature of modern living in the developed world and are common around the globe. They provide a cheap way of securing many things, including buildings and vehicles. It is common for people to carry the set of keys they need for their day to day activities around with them, often linked by a keyring adorned by key fobs and known as a keychain.