Grammatical particle  In grammar the term particle (abbreviated ) 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. 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. Depending on context, the meaning of the term may overlap with concepts such as "morpheme", "marker", or even "adverb" as in English phrasal verbs such as "out" in "get out". Under a strict definition, in which a particle must be uninflected, English deictics like "this" and "that" would not be classed as such (since they have plurals and are therefore inflected), and neither would Romance articles (since they are inflected for number and gender). This assumes that "any" function word incapable of inflection is by definition a particle. However, this conflicts with the above statement that particles have no specific lexical function per se, since non-inflecting words that function as articles, prepositions, conjunctions, interjections have a clear lexical function. This disappears if particles are taken to be a separate class of words, where one characteristic (which they share with some words of other classes) is that they do not inflect. "Particle" is a somewhat nebulous term for a variety of small words that do not conveniently fit into other classes of words. "The Concise Oxford Companion to the English Language" defines a particle as a "word that does not change its form through inflection and does not fit easily into the established system of parts of speech". The term includes the "adverbial particles" like "up" or "out" in verbal idioms (phrasal verbs) such as "look up" or "knock out"; it is also used to include the "infinitival particle" "to", the "negative particle" "not", the "imperative particles" "do" and "let", and sometimes "pragmatic particles" like "oh" and "well". The following particles can be considered the most prominent in Afrikaans:  There are three types of zhùcí (助詞; particles) in Chinese: Structural, Aspectual, and Modal.