Viola
When people see the viola, sometimes they think it is a violin.  This is because the viola is only a little larger than a violin, and like the violin, the viola is held on the player's left shoulder.  It is also because the sound of the viola is only five notes lower than the sound of the violin. The biggest difference between the viola and the violin is the sound. The viola's lowest string is the "C" string and its highest string is the "A" string. So, to see whether a violin-like instrument is a violin or viola, one will need to pluck the thinnest string. The violin's lowest string is the "G" string and its highest string is the "E" string.  Even though the viola and violin can play many of the same notes, they each have a special sound quality.  Sometimes people describe the viola's sound as more "dark", "earthy", or "mellow" than the violin's sound.