What is Bed?

Legal Definition
A bed is a piece of furniture which is used as a place to sleep or relax.

Most modern beds consist of a soft, cushioned mattress on a bed frame, with the mattress resting either on a solid base, often wood slats, or a sprung base. Many beds include a box spring inner-sprung base, a large mattress-sized box containing wood and springs that provide additional support and suspension for the mattress. Beds are available in many sizes, ranging from infant-sized bassinets and cribs, small beds for a single child or adult, to large queen and king-size beds designed for two adults. While most beds are single mattresses on a fixed frame, there are other varieties, such as the murphy bed, which folds into a wall, the sofa bed, which folds out of a sofa, and the bunk bed, which provides two mattresses on two tiers. Temporary beds include the inflatable air mattress and the folding camp cot. Some beds contain neither a padded mattress nor a bed frame, such as the hammock and they are considered one of the most comfortable places to rest while swaying side to side.

Beds may have a headboard for resting against, with others also having side rails and footboards (or "footers"). "Headboard only" beds may incorporate a "dust ruffle", "bed skirt", or "valance sheet" to hide the bed frame. To support the head, a pillow made of a soft, padded material is usually placed on the top of the mattress. Some form of covering blanket is often used to insulate the sleeper, often bed sheets, a quilt, or a duvet, collectively referred to as bedding. Bedding is the removable non-furniture portion of a bed, which enables these components to be washed or aired out.
-- Wikipedia
Legal Definition
1. The hollow or channel of a water-course ; the depression between the banka worn by the regular and usual flow of the water. "The bed is that soil so usually covered by water as to be distinguishable from the banks by the character of the soli, or vegetation, or both, produced by the common presence and action of flowing water." Howard v. Ingersoll, 13 How. 427, 14 L. Ed. 189. And see Paine Lumber Co. v. In S. (C. C.) 55 Fed. 864; Alabama v. Georgia, 23 How. 515, 16 L. Eld. 556; Haight v. Keokuk, 4 Iowa, 213; Puiley v. Municipality No. 2, 18 La. 282; Harlan, etc., Co. v. Paschali, 5 Del. Ch. 463.

2. The right of cohabitation or marital intercourse; as in the phrase "divorce from bed and board," or a mensa et thoro. See Bed of justice.
-- Black's Law Dictionary