1. Someone who presides over a forum or debate
   "The moderator ensured that all candidates had equal speaking time during the political debate"
    
2. Someone who mediates disputes and attempts to avoid violence
   "The moderator facilitated discussions between the two opposing groups"
    
3. In the Presbyterian church, the officer who presides over a synod or general assembly
   "The moderator called the annual synod meeting to order"
    
4. Any substance used to slow down neutrons in nuclear reactors
   "Heavy water is commonly used as a moderator in nuclear power plants"

Derived forms: moderators

Type of: go-between, inhibitor, intercessor, intermediary, intermediate, intermediator, mediator, presiding officer

Part of: nuclear reactor, reactor

Encyclopedia: Moderator