headrest vs ottoman

headrest

noun
  • The part of a seat designed to support the sitter's head. 

ottoman

noun
  • A low stool or thick cushion used to rest the feet or as a seat. 

  • An upholstered sofa, without arms or a back, sometimes with a compartment for storing linen etc. 

  • A fabric with a pronounced ribbed or corded effect, often made of silk or a mixture of cotton and silk-like yarns. 

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