put down vs aviation

put down is not a noun while aviation is a noun.

Word	Noun	Adjective	Verb	Adverb
put down	No	No	Yes	No
aviation	Yes	No	No	No

put down (noun)	aviation (noun)
	travel via aircraft
	the art of operating aircraft
	the aggregation of a country's military aircraft
	the operation of aircraft to provide transportation

put down (verb)	aviation (verb)
put down in writing; of texts, musical compositions, etc.
make a record of; set down in permanent form
put in a horizontal position
remove (cargo, people, etc.) from and leave
cause to sit or seat or be in a settled position or place
put (an animal) to death
reduce in worth or character, usually verbally
cause to come to the ground