- a person who presides at a town meeting, debate, assembly, etc.
- the presiding officer of a governing body, as of the Presbyterian Church
- a substance, as graphite or heavy water, used to slow down high-energy neutrons in a nuclear reactor
Origin: Middle English moderatour from Classical Latin moderator
Used by arrangement with John Wiley & Sons, Inc.
- One that moderates, as:a. One that arbitrates or mediates.b. One who presides over a meeting, forum, or debate.
- The officer who presides over a synod or general assembly of the Presbyterian Church.
- Physics A substance, such as water or graphite, that is used in a nuclear reactor to decrease the speed of fast neutrons and increase the likelihood of fission.
moderator - Science Definition
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