Does a harpsichord have two or three sets of keys?

A harpsichord typically has one set of keys, but it can have multiple manuals (keyboards) or registers (sets of strings) that can be activated to produce different sounds. Some harpsichords may have two manuals, allowing for greater versatility in performance. Each manual usually controls its own set of strings, enabling a range of tonal colors. Thus, while there are multiple features, the harpsichord itself has a single set of keys.