From Encyclopedia Jr, free information reference for Kids
The concert-master (or concertmaster, leader, also concertmistress) is the leader of the first violin section of a symphony orchestra. Any violin solo in an orchestral work is played by the concertmaster (except in the case of a concerto, in which case guest soloists may be heard).
The concertmaster makes decisions regarding bowing and other technical details of violin playing for the violins, and sometimes all of the string players; and is in charge of leading the orchestra in tuning before concerts and rehearsals and other technical aspects of orchestra management.
The concertmaster in a standard wind band is the first-chair clarinet, and leads the ensemble's tuning. The concertmaster will walk onto stage prior to performing, take a bow, and receive applause on behalf of the ensemble. The first-chair clarinet concertmaster will, in common practice, play all solos for their instrument. Often the lead flutist will receive similar responsibilities to the clarinet concertmaster, depending on several factors such as age, skill and time spent in the ensemble.