armband vs waterwing

armband

noun
  • An inflatable band worn round the arms to keep afloat in water 

  • A band worn around the arm of the captain of a team. 

  • A band worn around the arm, usually to symbolize protest or mourning. 

waterwing

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