nightrobe vs robe

nightrobe

noun
  • A robe to be worn at night; a nightgown. 

robe

noun
  • A wardrobe, especially one built into a bedroom. 

  • A long loose outer garment, often signifying honorary stature. 

  • The skin of an animal, especially the bison, dressed with the fur on, and used as a wrap. 

  • The largest and strongest tobacco leaves. 

verb
  • To put on official vestments. 

  • To clothe; to dress. 

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