accompaniment
US /əˈkʌm.pən.ɪ.mənt/
UK /əˈkʌm.pən.ɪ.mənt/

1.
a musical part that supports or partners another instrument, voice, or group
:
•
The piano provided a beautiful accompaniment to the singer's voice.
•
She played the violin with a guitar accompaniment.
2.
something that is provided or occurs with something else
:
•
The wine was a perfect accompaniment to the meal.
•
Headaches are a common accompaniment to stress.