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 chairperson 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
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
They also get hooked up with other families in similar situations, to problem-solve and share stories together, overseen by a moderator.
—
Kat McGowan, NPR, 31 Dec. 2025
Democratic Senator Paul Douglas was invited to sit in the moderator’s chair.
—NBC news, 28 Dec. 2025
Most reactors of similar design slow down neutrons using materials like water or graphite (called moderators).
—Christopher McFadden, Interesting Engineering, 26 Dec. 2025
Reddit's chief moderator for the Providence subreddit said in an interview that he's been on the platform for about 15 years and remembers the trauma that false Boston Marathon report caused.
—Arkansas Online, 21 Dec. 2025
See All Example Sentences for moderator
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Kat McGowan, NPR, 31 Dec. 2025
Democratic Senator Paul Douglas was invited to sit in the moderator’s chair.
—NBC news, 28 Dec. 2025
Most reactors of similar design slow down neutrons using materials like water or graphite (called moderators).
—Christopher McFadden, Interesting Engineering, 26 Dec. 2025
Reddit's chief moderator for the Providence subreddit said in an interview that he's been on the platform for about 15 years and remembers the trauma that false Boston Marathon report caused.
—Arkansas Online, 21 Dec. 2025
See All Example Sentences for moderator
Cite this Entry
“Moderator.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/moderator. Accessed 6 Jan. 2026.
Copy CitationKids 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
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