Definition of "atomic"

atomic

/əˈtɒm.ɪk/

adjective
not comparable
1. (physics, chemistry) Of or relating to atoms; composed of atoms; monatomic.
2. Employing or relating to nuclear energy or processes.
  Quotations
  Before the atomic spy Allan Nunn May left Canada to go to London, a treff in London had to be arranged for him and another agent.
  1955, David J. Dallin, Soviet Espionage, page 495
3. Infinitesimally small.
4. Unable to be split or made any smaller.
  1. (programming, of a commit in a VCS) Containing a single change, as opposed to involving numerous unrelated changes.
  2. (logic, of a proposition) Lacking logical operators; unable to be made simpler in logical form.
5. (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.
  Quotations
  It also provides an atomic compareAndSet method (which if successful has the memory effects of both reading and writing a volatile variable) and, for convenience, atomic add, increment, and decrement methods.
  2006, Tim Peierls, Brian Goetz, Joshua Bloch, Joseph Bowbeer, Doug Lea, David Holmes, Java Concurrency in Practice, Pearson Education, page 325
noun
plural atomics
1. (computing) An atomic operation.