- 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"

- applying to essential legal principles and rules of right
"substantive law"

- basic and fundamental
"the essential feature"

- absolutely required and not to be used up or sacrificed

- of the greatest importance
"the all-important subject of disarmament"
"crucial information"
"in chess cool nerves are of the essence"

- absolutely necessary

- vitally necessary
"essential tools and materials"
"funds essential to the completion of the project"
"an indispensable worker"

- being or relating to or containing the essence of a plant etc
"essential oil"

1. Belonging to the essence, or that which makes an object, or class of objects, what it is.

"Majestic as the voice sometimes became, there was forever in it an essential character of plaintiveness." -- Hawthorne.

2. Hence, really existing; existent.

"Is it true, that thou art but a name, And no essential thing?" -- Webster (1623).

3. Important in the highest degree; indispensable to the attainment of an object; indispensably necessary.

"Judgment's more essential to a general Than courage." -- Denham.

"How to live? -- that is the essential question for us." -- H. Spencer.

4. Containing the essence or characteristic portion of a substance, as of a plant; highly rectified; pure; hence, unmixed; as, an essential oil. "Mine own essential horror." Ford.

5. (Mus.) Necessary; indispensable; -- said of those tones which constitute a chord, in distinction from ornamental or passing tones.

6. (Med.) Idiopathic; independent of other diseases.

Essential character
(Biol.), the prominent characteristics which serve to distinguish one genus, species, etc., from another.

Essential disease
Essential fever
(Med.), one that is not dependent on another.

Essential oils
(Chem.), a class of volatile oils, extracted from plants, fruits, or flowers, having each its characteristic odor, and hot burning taste. They are used in essences, perfumery, etc., and include many varieties of compounds; as lemon oil is a terpene, oil of bitter almonds an aldehyde, oil of wintergreen an ethereal salt, etc.; -- called also volatile oils in distinction from the fixed or nonvolatile.

1. Existence; being. [Obs.] Milton.

2. That which is essential; first or constituent principle; as, the essentials of religion.