What is the meaning of Crwth?

An archaic stringed instrument associated particularly with Wales, though once played widely in Europe, and characterized by a vaulted back and enough space for the player to stop each of the six strings on the fingerboard. Played variously by plucking or bowing.

crwth; fiddle, violin, viol

purring

hump, hunch on the back, convexity; hunchback; hunchbacked, rounded, bent, convex

anything of round or bulging shape, especially a vessel, basket, box

Source: wiktionary.org