evening dress vs robe

evening dress

noun
  • formal attire worn for evening social events. 

  • An elegant dress worn by women, especially for social events in the evening, an evening gown. 

robe

noun
  • 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. 

  • A wardrobe, especially one built into a bedroom. 

  • The largest and strongest tobacco leaves. 

verb
  • To put on official vestments. 

  • To clothe; to dress. 

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