Bed Sheets are a thin piece of fabric serving as a basic article of bedding.

Bed Sheets are thin compared to blankets. These rectangular pieces of cloth are widely mostly used as they provide hygiene, comfort & aesthetics. Commonly the mattress is made up of natural fabric, like cotton, linen, and blends of cotton and polyester but sometimes sheets are silk, rayon, and bamboo fiber. Bed sheets come in two main varieties--flat or fitted. A flat bed sheet is simply a rectangular sheet of cloth, while a fitted bed sheet has its four corners, and sometimes two or four sides, fitted with elastic, to be used only as a bottom sheet.

The purpose of a fitted bottom bed sheet is to keep it from slipping off the mattress while the bed is in use.