cloak vs duvet

cloak

noun
  • A blanket-like covering, often metaphorical. 

  • A long outer garment worn over the shoulders covering the back; a cape, often with a hood. 

  • That which conceals; a disguise or pretext. 

  • A text replacement for an IRC user's hostname or IP address, making the user less identifiable. 

verb
  • To cover up, hide or conceal. 

  • To render or become invisible via futuristic technology. 

  • To cover as with a cloak. 

duvet

noun
  • A quilt or usually flat cloth bag with a filling (traditionally down) and usually an additional washable cover, used instead of blankets; often called a comforter or quilt, especially in US English. 

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