CELLO
... stringed instrument and part of the violin family. The cello is much larger than a violin, and unlike that instrument, it is played in an upright position between the legs of the seated musician, resting on a metal spike, called the endpin. The player draws his or her bow horizontally across the strings. Cellists usually play notes on the bass clef, and has four strings tuned in fifths: C (the lowest), G, D and A (below middle C); these are tuned exactly one octave below the viola. For the higher notes, the cello sometimes uses the tenor clef and occasionally the treble clef ..."
WikiPedia - Cello