On which keyboard instrument is a plectra used to pluck a set of strings?

The harpsichord is the keyboard instrument that utilizes plectra to pluck a set of strings. This is a key distinction because while the piano, organ, and accordion employ other mechanisms to produce sound, the harpsichord's unique action involves plucking the strings with plectra made typically from materials like quill or plastic.

In the construction of a harpsichord, when a key is pressed, the plectrum rises and catches the string, causing it to vibrate and produce sound. This results in a distinctive, bright tone that is characteristic of the instrument. The use of plectra contrasts with the hammers in a piano that strike the strings, or the air-driven pipes of an organ, emphasizing the harpsichord's distinctive approach to sound production. The accordion, while it has keys, generates sound through free reeds, further differentiating it from the plucking action of the harpsichord’s plectra.