Airway

n. air lane, route through the air travelled by aircraft; passageway through which air travels (Medical); ventilator shaft

The airways are those parts of the respiratory system through which air flows, to get from the external environment to the alveoli.The airway begins at the mouth or nose, and accesses the trachea via the pharynx. The trachea branches into the left and right main bronchi at the carina, situated at the level of the second thoracic vertebra. The bronchi branch into large bronchioles, one for each lobe of the lung. Within the lobes, the bronchi further subdivide some 20 times, ending in clusters of alveoli.
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Airway /air·way/ 1. the passage by which air enters and leaves the lungs. 2. a device for securing unobstructed respiration. [more]Airway - Community and Resources

Noun
1. a duct that provides ventilation (as in mines)
(synonym) air passage, air duct
(hypernym) duct
(hyponym) register
(part-meronym) vent, venthole, vent-hole, blowhole
2. a designated route followed by airplanes in flying from one airport to another
(synonym) air lane, flight path, skyway
(hypernym) path, route, itinerary
(hyponym) approach path, approach, glide path, glide slope
3. a commercial enterprise that provides scheduled flights for passengers
(synonym) airline, airline business
(hypernym) line
(part-meronym) fleet

noun
passage through which air passes, especially the trachea
airway clearing = making sure that the airways in a newborn baby or an unconscious person are free of any obstruction
airway obstruction = something which blocks the air passages