Flannel (fr. flanelle, from a Celtic word for wool) refers to the fabric’s surface rather than the material itself. Thus, flannel can be made from different types of fibres, but its brushed or combed surface gives it its characteristic softness and warmth.
Initially, we used wool to make flannel, but today, we use more cotton and other materials. The weave is a twill weave.
Sources
Sewport – What is Flannel Fabric: Properties, How its Made and Where 
Wikipedia – Flanell
November 2023, TÄNKOM | Revised March 2024 RETHINK
