essential vs necessary

essential and necessary both are nouns.

Word	Noun	Adjective	Verb	Adverb
essential	Yes	Yes	No	No
necessary	Yes	Yes	No	No

As nouns, essential and necessary are synonyms defined as:

Other synonyms of essential include necessity, requirement, requisite.

essential (noun)	necessary (noun)
anything indispensable	anything indispensable

essential (adjective)	necessary (adjective)
basic and fundamental	absolutely essential
defining rights and duties as opposed to giving the rules by which rights and duties are established	unavoidably determined by prior circumstances
being or relating to or containing the essence of a plant etc
of the greatest importance
absolutely necessary; vitally necessary