The crwth (/ˈkruːθ/ or /ˈkrʊθ/), also called a crowd or rote, is an archaic stringed instrument, associated particularly with Welsh music, once widely played in Europe. Four examples have survived and are to be found in St Fagans National History Museum Cardiff, National Museum Wales Aberystwyth, Warrington Museum & Art Gallery and Museum of Fine Arts, Boston.
The name crwth is originally a Welsh word, derived from a Proto-Celtic noun *krotto- ("round object") which refers to a swelling or bulging out, a pregnant appearance or a protuberance, and it is speculated that it came to be used for the instrument because of its bulging shape. Other Celtic words for violin also have meanings referring to rounded appearances. In Gaelic, for example, "cruit" can mean "hump" or "hunch" as well as harp or violin. Like several other English loanwords from Welsh, the name is one of the few words in the English language in which the letter W is used as a vowel.
The traditional English name is crowd (or rote), and the variants crwd, crout and crouth are little-used today. In Medieval Latin it is called the chorus or crotta. The Welsh word crythor means a performer on the crwth. The Irish word is cruit, although it also was used on occasion to designate certain small harps. The English surnames Crewther, Crowder, Crother and Crowther denote a player of the crowd, as do the Scottish names MacWhirter and MacWhorter.