1) an aircraft with one or more engines (aeroplane)

2) (the industry, science, of) flying aircraft (aviation)

3) a kind of aircraft with horizontal revolving blades (called rotors) on the top (helicopter)

4) a mixture of sugar, white of egg etc used for covering cake(s); the formation of ice, e.g. on the wings of an aircraft (icing)

5) (also Mach number) the ratio of the air speed of an aircraft to the speed of sound (mach)

6) a transport vehicle (especially an aircraft or spacecraft) that makes regular journeys to and from a place; (in a sewing-machine) a piece that carries the lower thread (shuttle)

7) the landing gear of an aircraft (undercarriage)