maestro (n.) Look up maestro at Dictionary.com
"master of music, great teacher or composer," 1797, from Italian maestro, literally "master," from Latin magisterium, accusative of magister (see master (n.)). Applied in Italian to eminent musical composers. Meaning "conductor, musical director" is short for maestro di cappella (1724), literally "master of the chapel" (compare German kapellmeister).