nightgown vs vestment

nightgown

noun
  • A dressing gown. 

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

vestment

noun
  • A robe, gown, or other article of clothing worn as an indication of office. 

  • Any of the special articles of clothing worn by members of the clergy etc., especially a garment worn at the celebration of the Eucharist. 

  • Clothing. 

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