cap
stan
Plural
capstans
1
a windlass rotated in a horizontal plane around a vertical axis; used on ships for weighing anchor or raising heavy sails
2
a rotating spindle used to apply tension, often used in musical instruments and other mechanical devices
A capstan is a cylindrical device used on some musical instruments to adjust the tension of the strings. It is often found on instruments like harpsichords and pianos. By turning the capstan, the musician can precisely tune the strings, which helps in maintaining proper pitch and tuning. The capstan usually works by pressing or pulling the strings through a mechanism that adjusts their tension.