airway vs register

airway and register both are nouns.

Word	Noun	Adjective	Verb	Adverb
airway	Yes	No	No	No
register	Yes	No	Yes	No

As nouns, register is a hyponym of airway; that is, register is a word with a more specific, narrower meaning than airway:

airway: a duct that provides ventilation (as in mines)
register: an air passage (usually in the floor or a wall of a room) for admitting or excluding heated air from the room

Other hyponyms of airway include breather, schnorchel, schnorkel, snorkel, snorkel breather, upcast, ventilation shaft.

airway (noun)	register (noun)
a commercial enterprise that provides scheduled flights for passengers	a regulator (as a sliding plate) for regulating the flow of air into a furnace or other heating device
a duct that provides ventilation (as in mines)	an air passage (usually in the floor or a wall of a room) for admitting or excluding heated air from the room
the passages through which air enters and leaves the body	a cashbox with an adding machine to register transactions; used in shops to add up the bill
a designated route followed by airplanes in flying from one airport to another	(computer science) memory device that is the part of computer memory that has a specific address and that is used to hold information of a specific kind
	(music) the timbre that is characteristic of a certain range and manner of production of the human voice or of different pipe organ stops or of different musical instruments
	an official written record of names or events or transactions
	a book in which names and transactions are listed

airway (verb)	register (verb)
	enter into someone's consciousness
	indicate a certain reading; of gauges and instruments
	record in a public office or in a court of law
	send by registered mail
	manipulate the registers of an organ
	be aware of
	show in one's face
	record in writing; enter into a book of names or events or transactions
	enroll to vote
	have one's name listed as a candidate for several parties