moderator

noun

1. any substance used to slow down neutrons in nuclear reactors

Definition categories: substance, inhibitor

2. in the Presbyterian church, the officer who presides over a synod or general assembly

Definition categories: person

3. someone who presides over a forum or debate

Definition categories: person

4. someone who mediates disputes and attempts to avoid violence

Definition categories: person, intercessor, intermediary, intermediator, mediator