Longman Dictionary of Contemporary English - accompaniment

~ n 1 music played at the same time as a song or a tune played on another instrument  (She starts by singing `Amazing Grace' with a simple guitar accompaniment.) 2 something that is provided or used with something else  (White wine makes an excellent accompaniment to fish.) 3 formal something that happens or exists at the same time as something else  (The job losses are an inevitable accompaniment of this reorganization.) 4 to the ~ of while another musical instrument is being played or another sound can be heard  (Singing to the accompaniment of a piano. | She left the stage to the accompaniment of loud cheers.)