PARTICLE

(SMALL PIECE) [noun] [C] - an extremely small piece of matterDust particles must have got into the motor, which is why it isn't working properly.(figurative) She wouldn't give me even the slightest particle (= the smallest amount) of information about what she'd been doing.A particle accelerator is a machine which makes extremely small pieces of matter travel at very high speeds, so that scientists can study the way they behave.