Other forms: particles
A particle is a piece of matter far too small for any eye to see. Dust at one end, and the building blocks of atoms at the other.
Physics uses it for electrons, protons and the rest, and a particle accelerator smashes them together to see what comes out. Environmental science uses it for the specks in air pollution, measured as particulates. Everyday use means any tiny fragment, as in particles of dust. Grammar has its own particle, meaning a small word like to or up that has no meaning on its own.
A particle is a little part. Latin particula is the diminutive of pars, so the physicist's particle is, grammatically, a small piece of something bigger.
Proto-Indo-European
*perh₃-
Latin
particula — small part, particle
Middle French
particule
English, today
particle
Built from
From Middle French particule, and its source, Latin particula (“small part, particle”), diminutive of pars (“part, piece”). Semantically displaced native Old English grot whence modern English groat.
Etymology from Wiktionary, CC BY-SA