modifier

A modifier is a word, phrase, or clause that restricts or describes another element in a sentence or expression. Modifiers add detail such as quality, quantity, size, time, or degree, and they help specify the meaning of the modified element. The term is used across language and computer science.

In linguistic grammar, modifiers attach to a head word or phrase, often forming adjectives, adverbs, or dependent clauses. Adjectival modifiers describe nouns (the red apple), adverbial modifiers describe verbs or adjectives (she sings very softly), and prepositional or participial phrases can modify nouns or verbs. Phrasal modifiers may be restrictive (essential to identify the head) or nonrestrictive (additional information, set off by commas). Misplaced or dangling modifiers can create ambiguity.

Common modifier types include adjectives, adverbs, participial phrases, relative clauses, and prepositional phrases. The position of modifiers can influence emphasis and clarity. In discourse, modifiers convey nuance such as approximation (about, nearly), degree (very, somewhat), and scope (each, all).

In programming, a modifier is a keyword or attribute that changes the properties of a declaration. Access modifiers determine visibility (public, private, protected). Other modifiers alter behavior or storage, such as static, final, const, abstract, volatile, or async. In some languages, modifiers also affect mutability, synchronization, or method overriding rules.

The word derives from Latin modificare, meaning to shape or form.