Flat sheet意思

"Flat sheet" is a term used in bedding to refer to a large rectangular piece of fabric that is used to cover a mattress. It is typically the top layer of bedding and is placed directly on top of the mattress. The flat sheet is usually tucked in at the bottom and sides to keep it in place, while the top of the sheet remains flat and smooth.

In contrast to a flat sheet, a fitted sheet has elastic around the edges to fit snugly on the mattress, and it is designed to be pulled over the corners of the mattress and tucked in. A duvet cover is another type of bedding that is used to cover a duvet or comforter, and it is similar to a flat sheet in that it is a large piece of fabric that is placed over the mattress, but it is used to cover a thicker layer of insulation rather than just the mattress itself.