Atom

At·om

Atom

n.
  1. An ultimate indivisible particle of matter. (Physics)
  2. The smallest particle of matter that can enter into combination; one of the elementary constituents of a molecule. (Chem.)
  3. Anything extremely small; a particle; a whit.
    There was not an atom of water.
    — Sir J. Ross.

Atom

v. t.
  1. To reduce to atoms. [Obs.]