atomic
Pronunciation: /əˈtɒmɪk/
adjective
- relating to an atom or atoms: the nature of matter at the atomic level the atomic nucleus
- Chemistry (of a substance) consisting of uncombined atoms rather than molecules: atomic hydrogen
- of or forming a single irreducible unit or component in a larger system: a society made up of atomic individuals pursuing private interests
- relating to or using the energy released in nuclear fission or fusion: the atomic age required a new way of political thinking atomic weapons

Origin:
late 17th century: from modern Latin atomicus, from atomus 'indivisible' (see atom)