subatom

/sʌbˈætəm/
noun
  1. A particle that is smaller than an atom, such as a proton, neutron, or electron.
    • Each subatom has a specific charge and mass that determines how atoms behave.
    • Scientists study subatoms to understand the fundamental building blocks of matter.
    • The accelerator collides subatoms at high speeds to discover new particles.
Synonyms