In music, instrumentation refers to the combination of instruments used to perform a song or piece, as well as the sound of each individual instrument. Musicians should be able to discern which instruments are playing at any given time. Songwriters and composers can greatly increase their creative choices by having a large mental vocabulary of instrument sounds at their disposal.

See also:
Instrumentation (Wikipedia)

Band Match will train your ear to recognize the sound of many different instruments and instrument combinations.