moderator

noun

mod·​er·​a·​tor ˈmä-də-ˌrā-tər 

plural moderators

1

: someone who presides over an assembly, meeting, or discussion: such as

a

: the chairman of a discussion group

b

: a person who administers an online forum, chat room, or group

c

: the nonpartisan presiding officer of a town meeting

d

: the presiding officer of a Presbyterian governing body

2

: one who arbitrates : mediator

3

: a substance (such as graphite) used for slowing neutrons in a nuclear reactor

moderatorship

ˈmä-də-ˌrā-tər-ˌship 

noun

Synonyms

• chairperson
• president
• chairman
• presider

Examples of moderator in a Sentence

The moderator allowed audience members to ask the governor questions.

She acts as the moderator in our office meetings.

Recent Examples on the Web

During that discussion, the moderator, CMS Administrator Dr. Mehmet Oz, mentioned that 49 percent of doctors are still responding to prior auth requests on paper. —Alexis Kayser, MSNBC Newsweek, 7 Aug. 2025

Paul Mitchell, the CEO of IAC and one of the moderators at the Monterey Physical AI Summit feels that in the space of < 1 year since the last panel was conducted in Indianapolis, understanding and application of physical AI has grown dramatically. —Sabbir Rangwala, Forbes.com, 7 Aug. 2025

The moderator is Beth Kassab, editor of the Winter Park Voice. —Joe Rassel, The Orlando Sentinel, 6 Aug. 2025

This was the real test of the moderator, in the end: being able to sift through, again and again, each workday’s thousand and one true things. —Literary Hub, 6 Aug. 2025

Word History

First Known Use

circa 1560, in the meaning defined at sense 2

Rhymes for moderator

• activator
• actuator
• agitator
• alligator
• allocator
• alternator
• animator
• annotator
• applicator
• arbitrator
• aspirator
• aviator

Kids Definition

moderator

noun

mod·​er·​a·​tor ˈmäd-ə-ˌrāt-ər 

1

: one that moderates: as

a

: the leader of a Presbyterian governing body

b

: the chairperson of a town meeting

c

: the chairperson of a discussion group (as on television)

2

: a substance (as graphite) used for slowing down neutrons in a nuclear reactor

Medical Definition

moderator

noun

mod·​er·​a·​tor ˈmäd-ə-ˌrāt-ər 

: a substance (as graphite, deuterium in heavy water, or beryllium) used for slowing down neutrons in a nuclear reactor