Grammatical particle

In grammar the term particle (abbreviated PTCL) has a traditional meaning, as a part of speech that cannot be inflected, and a modern meaning, as a function word associated with another word or phrase to impart meaning.

A particle is a part of speech that cannot be inflected, that is it can be neither declined nor conjugated. It is thus a broad category that can include various parts of speech. In English, the term particle is most commonly used for an adverbial particle, the preposition that follows the verb in phrasal verbs such as run through ("I have run through my earnings"), see through ("She is seeing the merger through"), or take off ("The business is about to take off"). In the wider sense of uninflected parts of speech, it may include: adjectives and adverbs, prepositions, conjunctions, and interjection. In addition, verbs in the infinitive form (to walk) and the definite article the are uninflected, and so may be considered particles.

In modern grammar, a particle is a function word that must be associated with another word or phrase to impart meaning, i.e., does not have its own lexical definition. On this definition, particles are a separate part of speech and are distinct from other classes of function words, such as articles, prepositions, conjunctions and adverbs. Languages vary widely in how much they use particles, some using them extensively and others more commonly using alternative devices such as prefixes/suffixes, inflection, auxiliary verbs and word order. Particles are typically words that encode grammatical categories (such as negation, mood, tense, or case), clitics, or fillers or (oral) discourse markers such as well, um, etc. Particles are never inflected.

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