A one-page dictionary entry defining the loom let-off, the mechanism that pays warp yarn off the yarn-beam at the rate the weaving process requires. It explains how let-off relates to pick rate, yarn and weft sizes and beating-up, and how it works together with the take-up onto the cloth-beam. A figure (Fig. 2903) illustrates a mechanism in which one cam operates both the take-up and let-off, with the whip-roll, arm, rod and pawls acting on the ratchet of the yarn-beam.