n. a long upholstered seat or couch having back and arms and often forming part of a suite; sofa.
Not originally Canadian, this term has become the generic word in Canada for this kind of couch, and, indeed, is often used for any kind of couch. It is still occasionally used in England and is heard locally in the United States, as in the northern counties of California.
1903  (1913)  He was leaning over the cushioned back of the Chesterfield upon which an old lady was seated . . . .
1918  [Advert.] Chesterfields, all-over upholstered frame, deep spring back, roll-shaped arms, and spring seat and edge covered in floral tapestry and velour, Reg. $110. for $85.00.
1939  Enjoying the privileges of a lifelong familiarity, he went to the chesterfield . . . and lay down flat on his back.
1965  [Caption] Looter carries out chesterfield on back.