The Concertmaster is the second-most significant person in an orchestra, symphonic band or other musical ensemble after the conductor or director. Another common term in the U.S. is "First Chair." In the U.K., the term commonly used is "leader."

In an orchestra, the concertmaster is the leader of the first violin section. There is another violin section, the second violins, led by the principal second violin. Any violin solo in an orchestral work is played by the concertmaster (except in the case of a concerto, in which case a guest soloist usually plays). It is usually required that the concertmaster be the most skilled musician in the section, experienced at learning music quickly, counting rests accurately and leading the rest of the string section by his or her playing and bow gestures.

The concertmaster sits to the conductor's left, closest to the audience, in what is called the "first chair," "first music stand" or "first desk".

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