What is the difference between a piano and a harpsichord?

A harpsichord is an instrument with a keyboard, but the strings are not hit by a hammer like at a piano, but are plucked. A harpsichord was developed and built before the piano was invented. A harpsichord has a different sound than a piano. Another difference is that it is not possible to play with different volume levels on a harpsichord. Playing in a dynamic way was the main driver for developing the piano, which was therefore call piano-forte, which means quietly-loud.