atomic (Adjective) — Of or relating to or comprising atoms. ex. "atomic structure" ex. "atomic hydrogen"
atomic (Adjective) — (weapons) deriving destructive energy from the release of atomic energy. ex. "atomic bombs"
atomic (Adjective) — Immeasurably small.
atomic (Adjective) — Unable to be split or made any smaller. ex. "A bit is an atomic item of data"