The viola is a bowed string instrument. It is slightly larger than a violin in size and has a lower and deeper sound than a violin. Since the 18th century it has been the middle voice of the violin family, between the violin (which is tuned a perfect fifth above it) and the cello (which is tuned an octave below it).
The strings of a modern symphony orchestra make up the largest family of instruments in the orchestra. This family is made up of five sections consisting of first violins, second violins, violas, cellos and basses.