As a Noun: 1. [Often the movement is repeated] the part of a door, a drawer, or a suitcase which you use to keep it shut and to prevent other people from opening it. To open it, you must first put a key in it and turn it. English = lock. 2. [Often the movement is repeated] a specially shaped piece of metal which you place in a lock and turn in order to open or lock a door, a drawer, or a suitcase; a specially shaped piece of metal that you turn, for example to wind up a clock. English = key. 3. [Often the movement is repeated] the keyhole in the dashboard of a car in which you insert a key in order to start the engine. English = ignition. As a Verb or Adjective: 1. To put a key into a lock and turn it so that it cannot be opened. English = lock. 2. To make sure all the doors and windows of a building are properly closed and locked so that burglars cannot get in. English = lock up. 3. To insert a key into the ignition of a car and turn it so that the engine starts.