particle
n. countablen. a tiny piece of something, like dust or sand. In grammar, it is a short word that does not change its form, such as 'up' in 'wake up'.
n. a minute portion of matter; in linguistics, a minor part of speech that does not undergo inflection and lacks a clear lexical category. Often functions as a component of phrasal verbs or as a marker of grammatical relationship.
A tiny particle of dust got into my eye.
The scientist used a microscope to observe how each particle moved in the liquid.
In the sentence 'she turned the light off', the word 'off' acts as a particle that modifies the verb's meaning rather than functioning as a traditional preposition.
From Middle French particule, and its source, Latin particula (“small part, particle”), diminutive of pars (“part, piece”).
In linguistics, the term typically refers to words like 'not', 'to' in infinitives, or the second part of a phrasal verb.