accompany on a musical instrument
1. To travel with one. This phrase can be used in reference to both people and things. While I enjoy spending time alone, I sometimes wish I had someone to accompany me on vacations. Pete's dog was more than happy to accompany him to the park. My cell phone always accompanies me when I leave the house.
2. To play a musical instrument in support of a featured band or performer. While her little sister played the flute, Sarah accompanied her on the clarinet. Will you accompany me on piano when I sing at the talent show?
See also: accompany
accompany someone on a musical instrument
to provide complementary instrumental music for someone's musical performance. Sally accompanied the singer on the piano.