nightgown vs regalia

nightgown

noun
  • A dressing gown. 

  • A long loose robe worn mainly by women for sleeping in. 

regalia

noun
  • Finery, magnificent dress, or lavish or flashy costume. 

  • The emblems, symbols, or paraphernalia indicative of royalty or any other sovereign status; such as a crown, orb, sceptre or sword. 

  • Traditional dress and accessories of North American Indigenous nations worn for ritual purposes. 

  • Royal rights, prerogatives and privileges actually enjoyed by any sovereign, regardless of his title (emperor, grand duke etc.). 

  • Decorations or insignia indicative of an office or membership of an order or society; such as freemasonry. 

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