noun. undefined

noun. A passageway or shaft in which air circulates, as in ventilating a mine.

noun. The upper passages of the respiratory system by which air reaches the lungs.

noun. undefined

noun. An airline.

noun. A regular route of travel for aircraft.

noun. Any passage in a mine used for purposes of ventilation; an air-course.

noun. a duct that provides ventilation, as in mines.

noun. The trachea.

noun. A flight path used by aeroplanes.

noun. the passages through which air enters and leaves the body

noun. a duct that provides ventilation (as in mines)

noun. a commercial enterprise that provides scheduled flights for passengers

noun. a designated route followed by airplanes in flying from one airport to another