atom Definition

atom
noun

1. The smallest unit of a chemical element that can display the properties of that element, and which is capable of combining with other atoms to form molecules.
2. formerly
The smallest particle of matter capable of existing.
3. non-technical
A very small amount or quantity; a tiny piece.
Thesaurus: speck, particle, bit, iota, grain, crumb, morsel, scrap, mite.

Etymology: 15c: from Greek atomos something that cannot be divided, from temnein to cut.