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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
    
4. Unable to be split or made any smaller
   "A bit is an atomic item of data"

See also: little, small, thermonuclear

Encyclopedia: Atomic, Molecular, and Optical physics Atomic Atomic, biological and chemical warfare Atomic, molecular, and optical physics Atomic, molecular, & optical physics