a powerful and expressive bow-instrument of the violin family. It has four strings, the third and fourth of which are covered with silvered copper wire. It is tuned C, G, D, A, reckoning upwards, and is an octave lower than the viola. Passages of rapid execution do not suit this instrument, especially on the third and fourth strings. The best violoncellos are those of the old Italian and Tyrolean makers. (See article Music.)