from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Constituting or being part of the essence of something; inherent.
- adj. Basic or indispensable; necessary: essential ingredients. See Synonyms at indispensable.
- adj. Medicine Of, relating to, or being a dysfunctional condition or a disease whose cause is unknown: essential hypertension.
- adj. Biochemistry Being a substance that is required for normal functioning but cannot be synthesized by the body and therefore must be included in the diet: essential amino acids.
- n. Something fundamental.
- n. Something necessary or indispensable.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Necessary.
- adj. Very important; of high importance.
- adj. Being in the basic form; showing its essence.
- adj. Such that each complementary region is irreducible, the boundary of each complementary region is incompressible by disks and monogons in the complementary region, and no leaf is a sphere or a torus bounding a solid torus in the manifold.
- adj. Idiopathic.
- n. A necessary ingredient.
- n. A fundamental ingredient.
from the GNU version of the Collaborative International Dictionary of English
- adj. Belonging to the essence, or that which makes an object, or class of objects, what it is.
- adj. Hence, really existing; existent.
- adj. Important in the highest degree; indispensable to the attainment of an object; indispensably necessary.
- adj. Containing the essence or characteristic portion of a substance, as of a plant; highly rectified; pure; hence, unmixed.
- adj. Necessary; indispensable; -- said of those tones which constitute a chord, in distinction from ornamental or passing tones.
- adj. Idiopathic; independent of other diseases.
- n. Existence; being.
- n. That which is essential; first or constituent principle.
from The Century Dictionary and Cyclopedia
- Involved in the essence, definition, or nature of a thing or of a word: as, an essential character; an essential quality.
- Constituting or making that which is characteristic or most important in a thing; fundamental; indispensable: as, an essential feature of Shakspere's style.
- Specifically, in medicine, idiopathic, not symptomatic merely.
- Pertaining to or proceeding from an essence; of the nature of an essence or extract.
- n. Existence; being.
- n. A fundamental or constituent principle; a distinguishing characteristic.
- In geology, noting those minerals of any species of rock which establish its character and which must be mentioned in its definition: contrasted with accessory.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. being or relating to or containing the essence of a plant etc
- adj. of the greatest importance
- adj. basic and fundamental
- adj. absolutely necessary; vitally necessary
- adj. defining rights and duties as opposed to giving the rules by which rights and duties are established
- n. anything indispensable
From Late Latin essentialis, from Latin essentia ("being, essence"). (Wiktionary)