particle

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A very small piece or part; a tiny portion or speck.
2. n. A very small or the smallest possible amount, trace, or degree: not a particle of doubt.
3. n. Physics A body whose spatial extent and internal motion and structure, if any, are irrelevant in a specific problem.
4. n. Physics An elementary particle.
5. n. Physics A subatomic particle. See Table at subatomic particle.
6. n. Linguistics An uninflected item that has grammatical function but does not clearly belong to one of the major parts of speech, such as up in He looked up the word or to in English infinitives.
7. n. Linguistics In some systems of grammatical analysis, any of various short function words, including articles, prepositions, and conjunctions.
8. n. Roman Catholic Church A small piece of a consecrated host.
9. n. Roman Catholic Church One of the smaller, individual hosts.
10. n. Archaic A small division or section of something written, such as a clause of a document.

Century Dictionary and Cyclopedia

1. n. A small part or piece, especially a small part or portion of some material substance: as, a particle of dust.
2. n. Specifically, any very small piece or part of anything: absolutely, a minute quantity; anything very small; an atom; a bit: as, he has not a particle of patriotism or virtue; are you fatigued? Not a particle.
3. n. In grammar, a part of speech that is considered of minor consequence, or that plays a subordinate part in the structure of the sentence, as connective, sign of relation, or the like: such are especially conjunctions, prepositions, and the primitive adverbs. The term is loose and unscientific.
4. n. Synonyms and Particle, Atom, Molecule, Corpuscle,iota, jot, mite, tittle, whit, grain, scrap, shred, scin-tilla. Atom and molecule are exact scientific terms; the other two of the italicized words are not. A particle is primarily a minute part or piece of a material substance, or, as in the case of dust, pollen, etc., a substance that exists in exceedingly minute form. Corpuscle is a somewhat old word for particle, to which it has almost entirely yielded place, taking up instead a special meaning in physiology. See definitions; see also part, n.
5. n. In a document of any kind, a very small part of any statement or proposition; a clause.
6. n. In the Roman Catholic Church, the host given to each lay communicant.
7. n. In mech., a body or portion of matter so minute that, while it possesses mass, it may be treated as a geometrical point.

GNU Webster's 1913

1. n. A minute part or portion of matter; a morsel; a little bit; an atom; a jot.
2. n. Any very small portion or part; the smallest portion.
3. n. A crumb or little piece of consecrated host.
4. n. The smaller hosts distributed in the communion of the laity.
5. n. (Gram.) A subordinate word that is never inflected (a preposition, conjunction, interjection); or a word that can not be used except in compositions.
6. n. (Physics) An elementary particle.

WordNet 3.0

1. n. (nontechnical usage) a tiny piece of anything
2. n. a function word that can be used in English to form phrasal verbs
3. n. a body having finite mass and internal structure but negligible dimensions