The noun essential has 1 sense (first 1 from tagged texts)
1. (1) necessity, essential, requirement, requisite, necessary -- (anything indispensable; "food and shelter are necessities of life"; "the essentials of the good life"; "allow farmers to buy their requirements under favorable conditions"; "a place where the requisites of water fuel and fodder can be obtained")
Overview of adj essential
The adj essential has 6 senses (first 3 from tagged texts)
1. (17) essential, indispensable -- (absolutely necessary; vitally necessary; "essential tools and materials"; "funds essential to the completion of the project"; "an indispensable worker")
2. (15) essential -- (basic and fundamental; "the essential feature")
3. (8) all-important, all important, crucial, essential, of the essence -- (of the greatest importance; "the all-important subject of disarmament"; "crucial information"; "in chess cool nerves are of the essence")
4. essential -- (being or relating to or containing the essence of a plant etc; "essential oil")
5. substantive, essential -- (defining rights and duties as opposed to giving the rules by which rights and duties are established; "substantive law")
6. essential -- (absolutely required and not to be used up or sacrificed)