hydrosphere vs main

hydrosphere and main both are nouns.

Word	Noun	Adjective	Verb	Adverb
hydrosphere	Yes	No	No	No
main	Yes	Yes	No	No

hydrosphere (noun)	main (noun)
the watery layer of the earth's surface; includes water vapor	a principal pipe in a system that distributes water or gas or electricity or that collects sewage
	any very large body of (salt) water

hydrosphere (adjective)	main (adjective)
	(of a clause) capable of standing syntactically alone as a complete sentence
	most important element
	of force; of the greatest possible intensity