As a Noun: 1. A method of providing a building, room or vehicle with cool dry air. English = air-conditioning. 2. A machine which keeps the air cool and dry in a room, building or vehicle. English = air-conditioner. As a Verb or Adjective: 1. Of a room, building or vehicle, to be supplied with air which is cool and dry by means of a special machine called an air-conditioner. English = (be) air-conditioned.