A bed is an item of furniture that is used as a place to sleep, rest, and relax. Most modern beds consist of a soft, cushioned mattress on a bed frame. The mattress rests either on a solid base, often wood slats, or a sprung base. Many beds include a box spring inner-sprung base, which is 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, to small beds for a single person or adult, to large queen and king-size beds designed for two people. 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, the trundle bed, which is stored under a low, twin-sized bed and can be rolled out to create a larger sleeping area, and the bunk bed, which provides two mattresses on two tiers as well as a ladder to access the upper tier. 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. Other beds are made specifically for animals. Beds may have a headboard for resting against, and may have side rails and footboards. "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. Etymology In Europe, mattresses were stuffed with straw, chaff, animal hair (for instance horsehair, used for its resilience), coarse wool, or down feathers, and stacked, softest topmost. This pile of mattresses, and the sheets, blanket, and pillows, was what early Europeans called a "bed"; it might be packed away during the day (a usage which survives in words like featherbed). The bedframe, even when present, supported the bed, but was not considered part of it. Later innovations made bedframes more portable, and increased their importance. History Prehistory In