›someone who controls and leads a discussion between a group of people, but does not take any side in it: A panel of business people will ask the candidates questions, with a local journalist as moderator. → Comparemediator
›INTERNETsomeone who makes sure that the rules of an internet discussion are not broken, for example by removing any threatening or offensive comments: She began posting on the message board and was later asked to be a moderator.