A cellone is a large cello invented in 1882 by the German luthier Alfred Stelzner. It is held like a cello but tuned (high-to-low) to E<sub>3</sub> A<sub>2</sub> D<sub>2</sub> G<sub>1</sub>, a fourth below the cello and two octaves below the violin. Its music is written in the bass clef. Its body length and its breadth slightly exceeds those of a normal cello, but it sounds much deeper than a normal cello.
It is rarely used by composers. One of the few works where it is used is the Sextet in D major for violino piccolo, violin, viola, violotta, cello, and cellone, Op. 68, by Arnold Krug.