It is the smallest instrument of strings bowed class, and its sound is treble. It is considered as the most important instrument of an orchestra.
The strings of modern violins are made with metal and the bow's shape is concave. To play it, the instrumentist lays the chin on the instrument in a piece called chin rest.
The so called old or baroque violin had gut strings and its bow had a convex shape, such as the hunting bows, and this shape allowed three strings being played simultaneously. In this case, the musician did not put the chin on the instrument.
Watch this video to find out more about violin.