necessity.

1. The state of being required or unavoidable under relevant conditions.

2. A thing required for life or a particular purpose.

Use it for

Words that belong together

• necessity of a condition
• practical necessity

On the page

The necessity of the condition was established by testing the cases that lacked it.

Practical necessity narrowed the choice without making the result logically inevitable.

Usage notes

Primary category: academic / formal. Forms: Usually uncountable; singular necessity and plural necessities for required things. Legacy lexical fields mirror sense 1 only. Use numbered sense fields for all meanings. Established modern English lexical item. No separate regional spelling or grammatical inflection entry. Writing functions: requirements and constraints, institutional organization, formal assessment, system properties. Disciplines: academic writing, formal analysis, institutional studies. Commonness: moderately common.