Fleece is a fabric created by brushing or shearing the loops on knit material to create raised, fuzzy fibers that trap air and provide insulation. Unlike French terry (where loops remain intact), fleece's brushed interior creates that distinctively soft, plush feeling associated with cozy sweatshirts. Traditional sweatshirt fleece is often cotton or cotton-poly blends; polar fleece (used for jackets) is typically 100% polyester. In streetwear, high-quality cotton fleece hoodies represent winter staples—warm, substantial, and comfortable. Premium fleece runs 400-500+ GSM, creating heavyweight pieces with presence. The trade-off for warmth is breathability: fleece retains heat, making it less versatile across seasons than French terry. Fleece can also pill over time with wear and washing, particularly lower-quality versions. Understanding fleece quality involves examining weight, fiber content (cotton vs. poly), and construction tightness. Vintage fleece from brands like Champion's Reverse Weave is particularly prized for its durability and the way it softens with age.