Dictionary
es•sen•tial
Pronunciation: (u-sen'shul), [key]—
adj.
1. absolutely necessary; indispensable:
Discipline is essential in an army.
2. pertaining to or constituting the essence of a thing.
3. noting or containing an essence of a plant, drug, etc.
4. being such by its very nature or in the highest sense; natural; spontaneous:
essential happiness.
5. Math.
a. (of a singularity of a function of a complex variable) noting that the Laurent series at the point has an infinite number of terms with negative powers.
b. (of a discontinuity) noting that the function is discontinuous and has no limit at the point. Cf.
removable (def. 2).
—
n.
a basic, indispensable, or necessary element; chief point:
Concentrate on essentials rather than details. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.