The violin is a bowed string instrument with four strings usually tuned in perfect fifths. It is the smallest and highest-pitched member of the violin family of string instruments, which also includes the viola and cello.
A violin typically consists of a spruce top (the soundboard, also known as the top plate, table, or belly), maple ribs and back, two endblocks, a neck, a bridge, a soundpost, four strings, and various fittings, optionally including a chinrest, which may attach directly over, or to the left of, the tailpiece. A distinctive feature of a violin body is its “hourglass” shape and the arching of its top and back. The hourglass shape comprises two upper bouts, two lower bouts, and two concave C-bouts at the “waist,” providing clearance for the bow.
The “voice” of a violin depends on its shape, the wood it is made from, the graduation (the thickness profile) of both the top and back, and the varnish which coats its outside surface. The varnish and especially the wood continue to improve with age, making the fixed supply of old violins much sought-after.
The four strings of the violin are fastened to the tailpiece, rest on the bridge of the violin, are suspended over the fingerboard, and run to the pegbox. At the pegbox, they are attached to tuning pegs which can be turned to alter the pitch of the string. By changing the position of his or her fingers on the fingerboard, different pitches are made. Then the player draws a bow across the strings at a right angle to produce a tone. The bow that is used is a narrow, slightly curved stick that is made of Pernambuco. It is about 75 cm. long and has a band of horse hair strung from one end to the other.