1. Of or relating to or comprising atoms
   "atomic structure"; "atomic hydrogen"
    
2. (weapons) deriving destructive energy from the release of atomic energy
   "atomic bombs";
   - nuclear
    
3. Immeasurably small
   "The atomic particles were too small to be seen even with an electron microscope"
    
4. Unable to be split or made any smaller
   "A bit is an atomic item of data"

See also: little, small, thermonuclear

Antonym: conventional

Encyclopedia: Atomic, biological and chemical warfare