Particle
late Middle English: from Latin particula ‘little part’, diminutive of pars, part- .
wiktionary
From Middle French particule, and its source, Latin particula(“small part, particle”), diminutive of pars(“part, piece”).
etymonline
particle (n.)
late 14c., "a bit or fragment, small part or division of a whole, minute portion of matter," from Latin particula "little bit or part, grain, jot," diminutive of pars (genitive partis) "a part, piece, division" (from PIE root *pere- (2) "to grant, allot"). In grammar, "a part of speech considered of minor consequence or playing a subordinate part in the construction of a sentence" (1530s). Particle physics, which is concerned with sub-atomic particles, is attested from 1969. In construction, particle board (1957) is so called because it is made from chips and shavings of wood.
