Necessary or necessity may refer to: * Need ** An action somebody may feel they must do ** An important task or essential thing to do at a particular time or by a particular moment * Necessary and sufficient condition, in logic, something that is a required condition for something else to be the case *

Necessary proposition Modal logic is a collection of formal systems developed to represent statements about necessity and possibility. It plays a major role in philosophy of language, epistemology, metaphysics, and natural language semantics. Modal logics extend other ...

, in logic, a statement about facts that is either unassailably true (tautology) or obviously false (contradiction) * Metaphysical necessity, in philosophy, a truth which is true in all possible worlds * Necessity in

modal logic Modal logic is a collection of formal systems developed to represent statements about necessity and possibility. It plays a major role in philosophy of language, epistemology, metaphysics, and natural language semantics. Modal logics extend other ...

Necessity good In economics, a necessity good or a necessary good is a type of normal good. Necessity goods are product(s) and services that consumers will buy regardless of the changes in their income levels, therefore making these products less sensitive to inc ...

in economics ;Law *

Doctrine of necessity The doctrine of necessity is the basis on which extra-constitutional actions by administrative authority, which are designed to restore order or attain power on the pretext of stability, are considered to be lawful even if such an action contrave ...

, a concept in constitutional law * Military necessity, a concept in international law *

Necessity (criminal law) In the criminal law of many nations, necessity may be either a possible justification or an exculpation for breaking the law. Defendants seeking to rely on this defense argue that they should not be held liable for their actions as a crime beca ...

, a defence in criminal law *

Necessity (tort) In tort common law, the defense of necessity gives the state or an individual a privilege to take or use the property of another. A defendant typically invokes the defense of necessity only against the intentional torts of trespass to chattels, t ...

, a concept in the law of tort * A necessity in contract law ;Other * , a poem by Letitia Elizabeth Landon being part of ''Three Extracts from the Diary of a Week'', 1837. * "Necessary" (song), by Every Little Thing, 1998 * A bathroom or toilet, in some languages (in English this is an archaic usage) * An economic need enunciated by US President Franklin D. Roosevelt in his 1944

Second Bill of Rights The Second Bill of Rights or Bill of Economic Rights was proposed by United States President Franklin D. Roosevelt during his State of the Union Address on Tuesday, January 11, 1944. In his address, Roosevelt suggested that the nation had come ...

* ''Necessity'' (novel), of 2016 by Jo Walton *

Necessary Records Necessary Records is a record label based in the UK, founded by Warren Clarke, a former A&R executive at London Records and Edel, in 2003. Clarke describes that the label was born out of a creative necessity. "It's an outlet for records that s ...

, UK record label

See also