essential vs primary

essential and primary both are nouns.

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

essential (noun)	primary (noun)
anything indispensable	a preliminary election where delegates or nominees are chosen
	one of the main flight feathers projecting along the outer edge of a bird's wing
	coil forming the part of an electrical circuit such that changing current in it induces a current in a neighboring circuit
	(astronomy) a celestial body (especially a star) relative to other objects in orbit around it

essential (adjective)	primary (adjective)
basic and fundamental	of first rank or importance or value; direct and immediate rather than secondary
defining rights and duties as opposed to giving the rules by which rights and duties are established	of or being the essential or basic part
being or relating to or containing the essence of a plant etc	most important element
of the greatest importance	not derived from or reducible to something else; basic
absolutely necessary; vitally necessary