A more thorough explanation:

A sidebar comment is an unnecessary and often argumentative remark made by an attorney or witness during a trial or deposition. It is called a "sidebar" because it is usually made at the side of the judge's bench, away from the jury and the rest of the courtroom.

For example, during a trial, a witness may make a sidebar comment that is not relevant to the case, or an attorney may make a comment that is intended to distract or confuse the jury. These comments can be disruptive and can interfere with the fair administration of justice.

Another example of a sidebar comment is when an attorney objects to a question asked by the opposing counsel. The judge may call for a sidebar to discuss the objection, and the attorneys may make comments or arguments that are not heard by the jury.

In summary, a sidebar comment is an unnecessary and often disruptive remark made during a trial or deposition. It can be made by an attorney or witness and is usually made at the side of the judge's bench. These comments can interfere with the fair administration of justice and should be avoided.