A blanket is a swath of soft cloth large enough either to cover or to enfold most of the user's body and thick enough to keep the body warm by trapping radiant body heat that otherwise would be lost through convection.
The term arose from the generalization of a specific fabric called Blanket fabric, a heavily napped woolen weave pioneered by Thomas Blanket (Blanquette), a Flemish weaver who lived in Bristol, England, in the 14th century. Earlier usage of the term is possible through its derivation from the French word for white: blanc. According to the Oxford English Dictionary, the word was used a noun as long ago as the 14th entury. William Shakespeare is recognised as the first person to use the verb blanket, meaning to 'cover with or as with a blanket'. In the play King Lear, published in 1608, the character Edgar says: "My face ile grime with filth, Blanket my loynes, else all my haire with knots."
Many types of blanket material, such as wool, are used because they are thicker and have more substantial fabric to them, but cotton can also be used for light blankets. Wool blankets are warmer and also relatively slow to burn compared to cotton. The most common types of blankets are woven acrylic, knitted polyester, mink, cotton, fleece and wool. Blankets also come with exotic crafting and exotic material such as crocheted afghan or a silk covering. The term blanket is often interchanged with comforter, quilt, and duvet, as they all have similar uses.
Blankets have been used by militaries for many centuries. Militaries are some of the biggest single consumers of woolen blankets. Military blankets tend to be coarse grey, with thick fibers of over 20 microns.
Blankets may be spread on the ground for a picnic or where people want to sit in a grassy or muddy area without soiling their clothing. Temporary blankets have been designed for this purpose.
Media related to Blankets at Wikimedia Commons The dictionary definition of blanket at Wiktionary