1. The waviness of a fibre expressed as crimps per unit length. 2. The difference in distance between two points on an unstretched fibre and the same two points when the fibre is straightened under specified tension. Crimp is expressed as a percentage of the unstretched length. 3. The difference in distance between two points on a yarn as it lies in a fabric and the same two points when the yarn has been removed from the fabric and straightened under specified tension, expressed as a percentage of the distance between the two points as the yarn lies in the fabric.