Key (lock) - Wikipedia, the free encyclopedia A key is a device that is used to operate a lock (such as to lock or unlock it). A typical key is a small piece of metal consisting of two parts: the blade, which slides ...
Key (music) - Wikipedia, the free encyclopedia In music theory, the key of a piece is the tonic note and chord which gives a subjective sense of arrival and rest. Other notes and chords in the piece create ...