region vs F layer

region and F layer both are nouns.

Word	Noun	Adjective	Verb	Adverb
region	Yes	No	No	No
F layer	Yes	No	No	No

region (noun)	F layer (noun)
a part of an animal that has a special function or is supplied by a given artery or nerve	the highest region of the ionosphere (from 90 to 600 miles up) which contains the highest concentration of free electrons and is most useful for long-range radio transmission
a knowledge domain that you are interested in or are communicating about
the extended spatial location of something
a large indefinite location on the surface of the Earth
the approximate amount of something (usually used prepositionally as in `in the region of')