- a : the presiding officer of a Presbyterian governing body
- b : the nonpartisan presiding officer of a town meeting
- c : the chairman of a discussion group
- 3: a substance (as graphite) used for slowing neutrons in a nuclear reactor
A moderator is an official of an incorporated town who presides over the town meeting, and in some cases, other municipal meetings. In the United States, the area of the country best known for the town meeting form of government is New England. The office of moderator exists in at least Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island and Vermont.