atom

at-om · noun

imported

Definitions

noun

  1. 1.

    The smallest unit of a chemical element that retains its chemical properties, consisting of a nucleus surrounded by electrons.

  2. 2.

    A very small amount of something.

Forms

plural: atoms

Phrases & expressions

  • •
    split the atom — Achieve nuclear fission; accomplish something groundbreaking.
  • •
    smash atoms — Conduct particle physics experiments.

Related words

See also: atomic, atoms, electron, molecule, nucleus
Synonyms: molecule, particle

Etymology

From Latin atomus, from Greek atomos ("indivisible"), from a- ("not") + tomos ("cutting"), from temnein ("to cut"). The ancient Greeks believed atoms were the smallest, indivisible units of matter.