A Dictionary of Music and Musicians/Fiddle
FIDDLE. The old English word, before 'viol' came in, and still the more idiomatic of the two. Both are possibly derived from the same root—vitula, a calf, from the springing motion of dancers (Dies and Littré; and compare the connection of Geige and jig). Fiddlestick is the violin-bow, as in the Epigram on a Bad Fiddler:—
Old Orpheus play'd so well he mov'd Old Nick,
Whilst thou mov'st nothing—but thy fiddlestick.
[ G. ]