diadem vs headband

diadem

noun
  • An ornamental headband worn as a badge of royalty. 

  • Regal power; sovereignty; empire—considered as symbolized by the crown. 

  • A crown. 

  • An arch rising from the rim of a crown (rarely also of a coronet), and uniting with others over its centre. 

verb
  • To adorn with a diadem; to crown. 

headband

noun
  • A strip of fabric worn around the head. 

  • A hair-accessory, made of a flexible material and curved like a horseshoe, for holding one's hair back. 

  • A strip of fabric attached to the top of the spine of a book; used as decoration and reinforcement. 

  • A thin slip of iron on the tympan of a printing-press. 

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