A minute portion of matter. The scientist examined the particle under the microscope.
A small fragment or quantity of something. There wasn't a particle of truth in his story.
A subatomic constituent of matter, such as a proton, neutron, or electron. Physicists study the behavior of particles in a collider.
A word or a part of a word that has a grammatical function but does not fit into the main parts of speech, such as 'up' in 'look up'. In the sentence 'He gave up', 'up' is a particle.