A record producer is an individual working within the music industry, whose job is to oversee and manage the recording (i.e. "production") of an artist's music.

An arrangement of a musical composition is a reworking of a piece of music so that it can be played by a different instrument or combination of instruments from the original. wikipedia.org

Audio post production is the general term for all stages of production happening between the actual recording in a studio and the completion of a master recording. It involves, sound design, sound editing, audio mixing, and the addition of effects. wikipedia.org

Audio editing is the process of taking recorded sound and changing it directly on the recording medium (analog) or in RAM (digital). wikipedia.org

Mastering, a form of audio post-production, is the process of preparing and transferring recorded audio from a source containing the final mix to a data storage device (the master); the source from which all copies will be produced (via methods such as pressing, duplication or replication). wikipedia.org

An audio engineer is a specialist in a skilled trade that deals with the use of machinery and equipment for the recording, mixing and reproduction of sounds. wikipedia.org