What type of fabric is characterized by a distinct twill line and is often used for suits?

Gabardine is a type of fabric that is primarily characterized by its distinctive diagonal weave known as twill, resulting in a textured surface and often a smooth hand feel. This weaving technique makes gabardine a durable and tightly woven fabric, which is ideal for structured garments such as suits and trousers. The twill line not only adds to the aesthetic appeal but also enhances the fabric's strength, making it suitable for formal attire.

In contrast, denim is typically heavier and characterized by a more casual look with its characteristic twill weave that is often used for jeans. Canvas is a robust fabric, usually made from cotton or a blend, and is more appropriate for casual items like bags and shoes rather than formalwear. Chiffon is a lightweight, sheer fabric often used in evening wear and formal dresses, known for its soft drape and transparency, which doesn't align with the structured nature of suits. Thus, gabardine is the most fitting choice when considering fabrics specifically used for suits.