Wrest Wrest, n. 1. The act of wresting; a wrench; a violent twist; hence, distortion; perversion. --Hooker. 2. Active or moving power. [Obs.] --Spenser. 3. A key to tune a stringed instrument of music. The minstrel . . . wore round his neck a silver chain, by which hung the wrest, or key, with which he tuned his harp. --Sir W. Scott. 4. A partition in a water wheel, by which the form of the buckets is determined. Wrest pin (Piano Manuf.), one of the pins around which the ends of the wires are wound in a piano. --Knight. Wrest plank (Piano Manuf.), the part in which the wrest pins are inserted.