particle

/ˈpɑrtɪkəl/
noun
  1. A very small piece or amount of something.
    • Scientists study the smallest particles of matter, like atoms and electrons.
    • There wasn't a single particle of evidence to support his claim.
    • A tiny particle of dust floated in the sunlight.
  2. In grammar, a short word that does not change form and often has a grammatical function, such as 'up' in 'give up' or 'to' in 'to go.'
    • In the phrasal verb 'turn off,' the word 'off' is a particle.
    • Some particles, like 'not,' help form negative sentences.
    • The infinitive marker 'to' is a grammatical particle.
  3. In physics, a tiny piece of matter or energy, such as an electron, proton, or photon.
    • The Large Hadron Collider smashes particles together at high speeds.
    • Physicists discovered a new subatomic particle in the experiment.
    • Light behaves both as a wave and as a particle called a photon.