ATOM

Definitions

1. 1. An ultimate indivisible particle of matter.
2. 2. An ultimate particle of matter not necessarily indivisible; a molecule.
3. 3. A constituent particle of matter, or a molecule supposed to be made up of subordinate particles.
4. 4. The smallest particle of matter that can enter into combination; one of the elementary constituents of a molecule.
5. 5. Anything extremely small; a particle; a whit. There was not an atom of water. Sir J. Ross.