atomic bomb vs superbomb

atomic bomb

noun
  • The possession of one or more atomic bombs; the ability to launch a nuclear attack. 

  • A nuclear weapon that obtains its destructive energy from nuclear fission. 

superbomb

noun
  • An extremely powerful bomb, especially the atomic bomb or hydrogen bomb. 

How often have the words atomic bomb and superbomb occurred in a corpus of books? (source: Google Ngram Viewer )