adjective
(physics, chemistry) Of or relating to atoms; composed of atoms; monatomic.
Employing or relating to nuclear energy or processes.
Infinitesimally small.
Unable to be split or made any smaller.
(computing, of an operation) Guaranteed to complete either fully or not at all while waiting in a pause, and running synchronously when called by multiple asynchronous threads.
noun
(computing) An atomic operation.