An arrangement is the interpretive transformation of a piece of music. It can extend to all of its structural characteristics, such as instrumentation, harmonization, rhythm, vocal performance, and even melody. If the piece is adapted only to another instrumentation, this is called transcription.

Especially in Jazz music, the original specifications for the performance of a piece are often incomplete and leave a lot of room for interpretation; the concrete arrangement for a particular band or occasion becomes accordingly important. Arrangements are often printed in score and are sometimes better known in this version than their originals.

Attention should be paid to the legal consequences: on the one hand, the originals can still be under copyright protection and arrangements must therefore be subject to authorization; on the other hand, arrangements themselves can be considered as separate works and thus protected by copyright.