Leonard, 1918–90, U.S. conductor, composer, and pianist.
British Dictionary definitions for Bernstein
Bernstein
/ˈbɜːnstaɪn; -stiːn/
noun
1.
Leonard. 1918–90, US conductor and composer, whose works include The Age of Anxiety (1949), the score of the musical West Side Story (1957), and Mass (1971)