The viola is a bowed string instrument. It is the middle voice of the violin family, between the violin and the cello.
The viola is similar in material and construction to the violin but is larger in size and more variable in its proportions. A "full-size" viola's body is between one and four inches longer than the body of a full-size violin (i.e., between 15 and 18 inches (38 and 46 cm)), with an average length of about 16 inches (41 cm). Small violas made for children typically start at 12 inches (30 cm), which is equivalent to a half-size violin. Often, a fractional-sized violin will be strung with the strings of a viola (C, G, D and A) for those children who need even smaller sizes^. Unlike the violin, the viola does not have a standard full size. The body of a viola would need to measure about 21 inches (53 cm) long to match the acoustics of a violin, making it impractical to play in the same manner as the violin. For centuries, viola makers have experimented with the size and shape of the viola, often tweaking the proportions or shape of the instrument to make an instrument with a shorter scale length and lighter weight, but that still has a large enough sound box to create an unmistakable "viola sound."

Playing the viola

Playing a 17" viola in 3rd position.

A person who plays the viola is called a violist or in other words, viola player. While it is similar to the violin, the technique required for playing viola has many differences. The difference in size accounts for some of the technical differences, as notes are spread out farther along the fingerboard often requiring different fingerings. The less responsive strings and heavier bow warrant a somewhat different bowing technique. The viola requires the player to lean more intensely on the strings compared to the violin.