Noun
(music) A soloist playing with a band or group of which he is not a regular member.
(MLE, derogatory) Somebody who is unimportant or irrelevant.
Source: en.wiktionary.orgRay had so much love of life and the music. He had so much integrity. He treated the music with so much dignity and respect. I spent four and a half years as a sideman with Ray Brown's trio. Music was his life, more so than anyone I could mention. Benny Green
I don't get offered leading parts. I suppose I've become a kind of character actor or sideman. I think it had to do with probably in the '90s, I refused so many leading roles that they gave up on me, or I just became unpopular, or I became old. All those reasons. Sam Shepard
For Davis, his departure from Parker's group marked the beginning of a period when he worked mainly as a freelancer and sideman in some of the most important combos on the New York City jazz scene. Source: Internet
For those with a fairly large property who want to try true composting, I’ll give you the rules as explained in University of Maine Cooperative Extension bulletins 1143 and 1159 and a MOFGA article written be now semi-retired crop specialist Eric Sideman. Source: Internet
David “Sideman” Whitley, resigned from the network after their initial decision to defend the use of the word on air. Source: Internet
Klinghoffer who had worked both as a sideman for the band on their Stadium Arcadium tour and on Frusciante's solo projects, replaced him as lead guitarist. Source: Internet