The cello is much larger than the viola or violin. You couldn't hold this under your chin! Instead, it is placed between the player's knees, resting on a peg, with the neck pointing over the player's left shoulder.

Because the cello body is bigger and its strings thicker than that of the violin or viola, the sound it makes is much deeper.

Even though the cello is
larger than the violin or the viola, that doesn't make it any harder to play.  A person who plays a cello is called a cellist.