Available Definitions:
1) n. - An ultimate indivisible particle of matter.
2) n. - An ultimate particle of matter not necessarily indivisible; a molecule.
3) n. - A constituent particle of matter, or a molecule supposed to be made up of subordinate particles.
4) n. - The smallest particle of matter that can enter into combination; one of the elementary constituents of a molecule.
5) n. - Anything extremely small; a particle; a whit.
6) v. t. - To reduce to atoms.