necessary

American  

[nes-uh-ser-ee] / ˈnɛs əˌsɛr i /

adjective

1. essential, indispensable, or requisite.

   The rotor is a necessary part of the motor.

   Synonyms:

   needed

   Antonyms:

   dispensable

2. happening or existing by necessity.

   The snow has forced a necessary change in our plans.

3. acting or proceeding from compulsion or necessity; not free; involuntary.

   a necessary agent.

4. Logic.

   1. (of a proposition) such that a denial of it involves a self-contradiction.

   2. (of an inference or argument) such that its conclusion cannot be false if its supporting premises are true.

   3. (of a condition) such that it must exist if a given event is to occur or a given thing is to exist.

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noun

plural

necessaries

1. something necessary or required for a particular purpose; necessity.

   Synonyms:

   essential, requisite, requirement

2. Law. necessaries, food, clothing, etc., required by a dependent person and varying with their social or economic position or that of the person upon whom they are dependent.

3. Chiefly New England. a privy or toilet.

necessary British  

/ ˈnɛsɪsərɪ /

adjective

1. needed to achieve a certain desired effect or result; required

2. resulting from necessity; inevitable

   the necessary consequences of your action

3. logic

   1. (of a statement, formula, etc) true under all interpretations or in all possible circumstances

   2. (of a proposition) determined to be true by its meaning, so that its denial would be self-contradictory

   3. (of a property) essential, so that without it its subject would not be the entity it is

   4. (of an inference) always yielding a true conclusion when its premises are true; valid

   5. (of a condition) entailed by the truth of some statement or the obtaining of some state of affairs Compare sufficient

4. philosophy (in a nonlogical sense) expressing a law of nature, so that if it is in this sense necessary that all As are B, even although it is not contradictory to conceive of an A which is not B, we are licensed to infer that if something were an A it would have to be B

5. rare compelled, as by necessity or law; not free

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noun

1. informal the money required for a particular purpose

2. informal to do something that is necessary in a particular situation

Related Words

Necessary, essential, indispensable, requisite indicate something vital for the fulfillment of a need. Necessary applies to something without which a condition cannot be fulfilled or to an inevitable consequence of certain events, conditions, etc.: Food is necessary to life. Multiplicity is a necessary result of division. Indispensable applies to something that cannot be done without or removed from the rest of a unitary condition: Food is indispensable to living things. He made himself indispensable as a companion. Something that is essential forms a vitally necessary condition of something: Air is essential to red-blooded animals. It is essential to understand the matter clearly. Requisite applies to what is thought necessary to fill out, complete, or perfect something: She had all the requisite qualifications for a position.

Other Word Forms

• necessariness noun
• quasi-necessary adjective

Etymology

Origin of necessary

First recorded in 1300–50; Middle English necessarie, from Latin necessārius “unavoidable, inevitable, needful,” equivalent to necess(e) (neuter indeclinable adjective) “unavoidable, necessary” + -ārius -ary

Related Words

• basic
• crucial
• decisive
• essential
• fundamental
• imperative
• indispensable
• mandatory
• needed
• paramount
• required
• significant
• unavoidable
• urgent
• vital