A-bomb vs hydrogen bomb

A-bomb

noun
  • An atomic bomb; a weapon that derives its energy from nuclear reactions and has enormous destructive power. 

verb
  • To bomb with an atom bomb. 

hydrogen bomb

noun
  • A thermonuclear bomb that derives its destructive power from the fusion of isotopes of hydrogen (deuterium and tritium). 

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