duvet vs quilt

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. 

quilt

noun
  • A bed covering consisting of two layers of fabric stitched together, with insulation between, often having a decorative design. 

  • A quilted skirt worn by women. 

  • A roll of material with sound-absorbing properties, used in soundproofing. 

verb
  • To construct a quilt. 

  • To construct something, such as clothing, using the same technique. 

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