To be even more pedantic, it’s a hammered dulcimer in a box. Dulcimers are a pretty broad family and not all are, well, hammered.

A piano is the result of a frustrated dulcimerist going “what I really need is to be able to wield more hammers at once. No, more than that. More.”

To be fair, I’d say a harpsichord is more of a guitar/lute/etc. in a box, given the twanginess of it.

Proposal: rescore all of J S Bach’s harpsichord concertos for six-string banjo.

One of my coworkers once described an accordion as “a piano that squashes”.

Strictly speaking, an accordion is a mutant harmonica.

slight correction: a BUTTON accordion is a mutant harmonica. a piano accordion is a box of oboes