definition of
particle

[1] #1 particle n. [atom, molecule, corpuscle, mote, speck] (nontechnical usage) a tiny piece of anything. wn

[2] #2 particle n. [subatomic particle] a body having finite mass and internal structure but negligible dimensions. wn

[3] #3 particle n. a function word that can be used in English to form phrasal verbs. wn