Pronunciation: (pär'ti-kul),[key] —n. 1. a minute portion, piece, fragment, or amount; a tiny or very small bit: a particle of dust; not a particle of supporting evidence. 2. Physics. a. one of the extremely small constituents of matter, as an atom or nucleus.
b. an elementary particle, quark, or gluon.
c. a body in which the internal motion is negligible.
3. a clause or article, as of a document.
4. Gram. a. (in some languages) one of the major form classes, or parts of speech, consisting of words that are neither nouns nor verbs, or of all uninflected words, or the like.
b. such a word.
c. a small word of functional or relational use, as an article, preposition, or conjunction, whether of a separate form class or not.
5. Rom. Cath. Ch.a small piece of the Host given to each lay communicant in a Eucharistic service.