Flannel is a soft, warm fabric with a slightly fuzzy surface, traditionally made from wool but now often made from cotton. If you've ever worn pajamas that feel cozy and a little bit brushed or napped, you've probably worn flannel. The fabric's surface has tiny fibers that stand up slightly, creating that characteristic softness that makes flannel perfect for cold weather.

Flannel shirts, often featuring plaid patterns in red, blue, or green, became iconic workwear for loggers and outdoorsmen because the fabric kept them warm while remaining comfortable for physical labor. Today, people wear flannel shirts casually, and flannel sheets are popular in winter because they feel warm the moment you climb into bed, unlike cold, smooth cotton sheets.

The word can also refer to a small cloth used for washing, especially in British English, where a flannel means a washcloth. Americans might say “washcloth” while the British would say “flannel” for that same small square of cloth you use to wash your face.

When someone talks about wearing their flannels, they usually mean comfortable flannel pajamas or a casual flannel shirt, the kind of clothing that feels like a warm hug on a chilly autumn day.