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 in a way that reflects the specific indications in that score, set the tempo, ensure correct entries by ensemble members, and "shape" the phrasing where appropriate. Conductors communicate with their musicians primarily through hand gestures, usually with the aid of a baton, and may use other gestures or signals such as facial expression and eye contact. A conductor usually supplements their direction with verbal instructions to their musicians in rehearsal.