A base layer is the first layer of clothing worn next to the skin. Its primary purpose is to wick moisture away from the body, keeping the wearer dry and comfortable during physical activities. Base layers are typically made from materials like merino wool, synthetic fabrics, or cotton, each offering different benefits in terms of warmth, breathability, and moisture management. Base layers come in various styles, including tops, bottoms, and even full-body suits. They are commonly used in outdoor activities such as hiking, skiing, and running, where temperature regulation and moisture control are essential for performance and comfort.