📒 a piece of metal with a special shape used for locking a door, starting a car, etc.
📒 a thing that makes you able to understand or achieve something
📒 any of the buttons that you press to operate a computer, phone or typewriter
📒 any of the wooden or metal parts that you press to play a piano and some other musical instruments
📒 a set of related notes, based on a particular note. Pieces of music are usually written mainly using a particular key.
📒 a set of answers to exercises or problems
📒 an explanation of the symbols used on a map or plan
📒 locked up safely somewhere; in prison