It could also refer to a prosecutor improperly or intentionally hiding evidence that does not go with their case (their theory of what happened) and could suggest or prove to the judge or jury that the defendant is not guilty or that (s)he is legally obligated to show the defense.
Also Rule 3.8 of the ABA Model Rules of Professional Conduct requires prosecutors to "make timely disclosure to the defense of all evidence or information that tends to negate the guilt of the accused or mitigates the offense."
As the U.S. Supreme Court stated in Simmons v. United States: "In order to effectuate the Fourth Amendment's guarantee of freedom from unreasonable searches and seizures, this Court long ago conferred upon defendants in federal prosecutions the right, upon motion and proof, to have excluded from trial evidence which had been secured by means of an unlawful search and seizure.
"[1] Because it is grounded in the right to be secure from unreasonable searches and seizures, a person must have standing to move to suppress evidence.
In other words, one cannot object to evidence obtained by an illegal search if it was someone else's privacy that was violated.