Manuductor

Manuductor is the name of an ecclesiastical officer whose duty it was to give the signal to the choristers to sing, to mark the measure, beat the time, and regulate the music. The word means to lead by means of the hand; and the officer was so called because he was required to stand in the middle of the aisle, and to guide the choir by the motions of his hand. The Greek Church has an officer who performs similar services, who is called Mesochoros, because he is seated in the midst of the choir.