Define "thermal insulation" in textiles.

Thermal insulation in textiles refers to the fabric's capability to retain body heat. This is particularly important in creating apparel that helps maintain warmth in cold environments. The fibers in thermal insulating fabrics trap air, which serves as an additional layer of insulation, minimizing heat loss from the body to the surrounding environment. This characteristic is essential for clothing like winter jackets, thermal underwear, and other outerwear designed for cold weather.

The ability to retain heat directly influences comfort and performance in low-temperature conditions, making it a key factor in textile engineering and clothing design. Materials engineered for thermal insulation often have specific structures or weights to enhance their heat retention properties without adding excessive bulk, ensuring that they are both functional and comfortable.

While other aspects of fabric, such as water repellency, breathability, and weight, are important in their own right and contribute to the overall performance of textiles, they do not define thermal insulation. Each of those features serves different purposes within the properties of textile materials.