The term 'CELLO RELATIVE' refers to two string instruments related to the cello. The first is the VIOL, which is a bowed string instrument of the Renaissance and Baroque eras. It is also known as the VIOLA da gamba, and is similar in size and shape to the cello. The second is the VIOLA, which is a bowed string instrument of the modern orchestra. It is slightly larger than the VIOL and is tuned a fifth higher than the cello.