main vs infrastructure

main and infrastructure both are nouns.

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

main (noun)	infrastructure (noun)
a principal pipe in a system that distributes water or gas or electricity or that collects sewage	the stock of basic facilities and capital equipment needed for the functioning of a country or area
any very large body of (salt) water	the basic structure or features of a system or organization

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