Muslin cloth

From CosplayWiki

Muslin is most typically a closely-woven unbleached or white cloth, produced from corded cotton yarn. Wide muslin is called "sheeting". It is often used to make dresses or curtains but may also be used to complement foam for bench padding.

When sewing clothing, a test or fitting garment may be made of inexpensive muslin fabric before cutting the intended expensive fabric, thereby avoiding a costly mistake. The muslin garment is often called a muslin and the process is called making a muslin. With the availability of inexpensive synthetic fabrics, which closely resemble the hand (drape and feel) of expensive natural fabrics, a test or fitting garment made of synthetics may still be referred to as a muslin, because the word has become the generic term for a test or fitting garment.