bezant vs roundel

bezant

noun
  • The heraldic representation of a gold coin. 

  • A coin made of gold or silver, minted at Byzantium and used in currency throughout mediaeval Europe. 

roundel

noun
  • A circular insignia painted on an aircraft to identify its nationality or service. 

  • A small circular shield, sometimes not more than a foot in diameter, used by soldiers in the fourteenth and fifteenth centuries. 

  • Anything having a round form; a round figure; a circle. 

  • A circular spot; a charge in the form of a small coloured circle. 

  • A roundelay or rondelay. 

  • A bastion of a circular form. 

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