Sofa - Styles ........... Illustrated FURNITURE Glossary.
Daybed / Day bed
Edgar G. Miller, Jr., American Antique Furniture, 1937, Vol. 1, p. 282
The word "day-bed" is defined as "a bed used for rest during the day".
A similar article is known in France as a "chaise long", meaning a "long chair". In our country they were known as "couches" in the period in which they were made, which was from about 1640 to 1780; and that name is preferred by the leading writer [L. V. Lockwood] on American antique furniture. The term "day-bed" is used in England and seems to be more descriptive of the use to which the piece was put than any other word; but the term "chaise lounge" more fully describes its appearance, as it is in fact a "long chair".
A day-bed may be described as a long chair without a back lengthwise, but having at one end a head-piece or a back "similar to a chair back of the period to which it belongs, with three pairs of front legs, making an elongated chair"; thus in the period of Chippendale the head-piece resembled the back of a Chippendale style chair. It was often so constructed that the head-piece was adjustable and could swing backwards or forwards, supported by chains or straps, giving a reclining position for the head of the occupant.
The seat and head-piece were of cane or rush in the early pieces, and were furnished with cushions; but the later ones were often upholstered. The wood was that used in the period, generally walnut in the earlier and mahogany in the later; but other woods were sometimes used.
the day-bed as an article of furniture had lost its vogue by the close of the seventeenth century, when the use of the bed-chamber as a reception room had also gone out of fashion.