Definitions for gag order
Random House Webster's College Dictionary
a court order prohibiting those involved in a case from discussing it publicly.
Origin of gag order:
a court order restricting information or comment by the participants involved in a lawsuit
"imposing a gag order on members of the press violates the First Amendment"
An order issued by a court prohibiting specified persons from discussing a case outside limitations set by the court.
Any directive from a person in authority prohibiting another person from speaking about a certain thing.