Bristle refers to a stiff, short hair or fiber, often found on animals like pigs or used in products like brushes. These stiff hairs can serve various purposes, such as providing protection or aiding in grooming. In the context of brushes, bristles are typically made from materials like nylon, polyester, or natural fibers. They are designed to effectively clean surfaces or apply paint, depending on the type of brush. The arrangement and stiffness of the bristles can greatly influence the brush's performance and suitability for different tasks.