Particle \Par"ti*cle\, n. [L. particula, dim of pars, gen partis, a part: cf. F. particule. See Part, and cf. Parcel.]

1. A minute part or portion of matter; a morsel; a little bit; an atom; a jot; as, a particle of sand, of wood, of dust.

The small size of atoms which unite To make the smallest particle of light. --Blackmore.

2. Any very small portion or part; the smallest portion; as, he has not a particle of patriotism or virtue.

The houses had not given their commissioners authority in the least particle to recede. --Clarendon.

3. (R. C. Ch.)
   (a) A crumb or little piece of concecrated host.
   (b) The smaller hosts distributed in the communion of the laity. --Bp. Fitzpatrick.

4. (Gram.) A subordinate word that is never inflected (a preposition, conjunction, interjection); or a word that can not be used except in compositions; as, ward in backward, ly in lovely.

Source: Webster's Revised Unabridged Dictionary (1913)