A (; from the French verb meaning 'to repeat, to go over, to rehearse') is an accompanist, tutor or coach of ballet dancers or opera singers. The feminine form is .
In opera, a is the person responsible for coaching singers and playing the piano for music and production rehearsals. When coaching solo singers or choir members, the ' will take on a number of the roles of a vocal coach: advising singers on how to improve their pitch and pronunciation, and correcting note or phrasing errors.
are skilled musicians who have strong sight-reading and score reading skills. In addition to being able to sight read piano parts, some ' can play on the piano an orchestral score reducing it in real-time (orchestral reduction), by reading from a large open score of all of the instruments and voice parts. ' are also skilled in following the directions of a conductor, in terms of changing the tempo, pausing, or adding other nuances.
In ballet, a ' teaches the steps and interpretation of the roles to some or all of the company performing a dance. Several late 20th-century choreographers, such as George Balanchine, Jerome Robbins, Gerald Arpino and Twyla Tharp, have established trusts and appointed conservatorsâÂÂhand-picked dancers who have intimate knowledge of particular balletsâÂÂas ' of their works.