necessarius

Necessarius is a Latin adjective meaning "necessary" or "essential," and it is often encountered in historical Latin texts. The word derives from the concept of necessity, with the noun necessitas meaning "necessity." The phrase necese est or neccessarily is used in Latin to indicate something that must be done, and necessarius forms the adjective and occasional substantive derivatives from that concept.

In classical Latin, necessarius typically described something required, indispensable, or bound by obligation. It could modify things deemed essential, such as tools, duties, or conditions, and it also appeared as a substantive in some contexts to denote a person or thing that is required for a given purpose. When used as a noun, necessarius could refer to a person who is deemed necessary for a task or function, though this usage is less common than the adjectival form.

In medieval and ecclesiastical Latin, necessarius appears in discussions of duties, obligations, or offices considered necessary within a community or institution. It could indicate roles assigned due to practical need, such as assistants, delegates, or other personnel required to fulfill a function. In canon law or clerical administration, the term may surface to describe actions or offices that are mandated by necessity rather than voluntary arrangement.

Today, necessarius survives mainly in scholarly works on Latin language and history. Its legacy lives on in modern Romance languages that derive from Latin, where cognates such as necessary or indispensable appear, though the Latin form necessarius is rarely used in contemporary prose outside academic contexts.