Muslin is a soft, lightweight cotton fabric with a loose, breathable weave. If you hold muslin up to the light, you can often see tiny gaps between the threads, which makes it perfect for hot weather or situations where air needs to flow through the material.

By the 1700s, muslin from India became so prized that wealthy Europeans paid extraordinary prices for the finest varieties, which were woven so delicately they could pass through a ring.

Today, muslin serves many practical purposes. Dressmakers use it to create test versions of garments before cutting into expensive fabric. Parents wrap babies in muslin blankets because the fabric is gentle and breathable. Cheesemakers strain cheese through muslin cloth. Photographers use muslin backdrops for portraits. Theater crews paint muslin sheets to create stage backgrounds.

The word can also describe the test garment itself: a dressmaker might drape a muslin on a mannequin to check how a design will look before sewing the real dress.