›(US usuallymediator)formalsomeone who tries to help other people come to an agreement: An independent moderator should be appointed to oversee the negotiations.Diplomacy and mediation›USsomeone who makes certain that a formal discussion happens without problems and follows the rules: He challenged the president to a series of TV debates. Just the two of them, with no moderator.Diplomacy and mediation›UKspecializedsomeone who makes certain that all the people marking an exam use the same standards: The final marks awarded for coursework will depend upon the moderator.People who analyse and judge›someone who makes sure that the rules of an internet discussion are not broken, for example by removing any threatening or offensive messages