essential

I

(New American Roget's College Thesaurus)

adj. substantial, material, constitutional, fundamental, elementary, absolute; necessary, needful, requisite, cardinal, indispensable, vital; inherent, intrinsic, basic. See necessity, part, importance. Ant., inessential, unimportant.

II

(Roget's IV) modif.

1. [Absolutely necessary]

Syn. imperative, required, indispensable, requisite, necessary, vital; see also crucial , necessary 1 .

2. [Rooted in the basis or essence]

Syn. basic, primary, quintessential; see fundamental 1 , inherent .

Syn.- essential , in strict usage, is applicable to that which constitutes the absolute essence or the fundamental nature of a thing and therefore must be present for the thing to exist, function, etc. [ food is essential to life ] ; an indispensable person or thing cannot be done without if the specified or implied purpose is to be achieved [ her diagnostic skills proved indispensable to the clinic ] ; requisite is applied to that which is required by the circumstances or for the purpose and generally suggests a requirement that is imposed externally rather than an inherent need [ the requisite experience for a position ] ; necessary implies a pressing need but does not always connote absolute indispensability

III

(Roget's 3 Superthesaurus)

I

n.

necessity, must, fundamental, basic, prerequisite, requirement, rudiment, cornerstone, indispensable element.

ANT.: nonessential, extra

II

a.

fundamental, important, vital, crucial, basic, prime, cardinal, necessary, elementary, indispensable, requisite.

ANT.: incidental, unessential, peripheral, superfluous

IV

(Roget's Thesaurus II) I adjective 1. Constituting or forming part of the essence of something: basic, constitutional, constitutive, fundamental, integral, vital. See BE, SURFACE. 2. Of or being an irreducible element: basic, elemental, elementary, fundamental, primitive, ultimate, underlying. See SURFACE. 3. Incapable of being dispensed with: indispensable, necessary, needful, required, requisite. See IMPORTANT, NECESSARY. II noun 1. A fundamental irreducible constituent of a whole: basic, element, fundamental, rudiment (often used in plural). Idiom: part and parcel. See PART. 2. Something indispensable: condition, must, necessity, need, precondition, prerequisite, requirement, requisite, sine qua non. See NECESSARY.