Conducting is the art of directing a musical performance, such as an orchestral or choral concert. It has been defined as "the art of directing the simultaneous performance of several players or singers by the use of gesture." The primary duties of the conductor are to interpret the score created by a composer in a manner which is reflective of the specific indications within that score, set the tempo, ensure correct entries by various members of the ensemble, and to "shape" the phrasing where appropriate. To convey their ideas and interpretation, conductors communicate with their musicians primarily through hand gestures, typically though not invariably with the aid of a baton, and may use other gestures or signals, such as eye contact with relevant performers. A conductor's directions will almost invariably be supplemented or reinforced by verbal instructions or suggestions to their musicians in rehearsal prior to a performance.