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moderator

[ mod-uh-rey-ter ]
/ ˈmɒd əˌreɪ tər /
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noun
a person or thing that moderates.
a person who presides over a panel discussion on radio or television.
a member of an online message board or electronic mailing list with privileges and responsibilities to approve or reject messages and uphold the terms of service.
a presiding officer, as at a public forum, a legislative body, or an ecclesiastical body in the Presbyterian Church.
Physics. a substance, as graphite or heavy water, used to slow neutrons to speeds at which they are more efficient in causing fission.
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Origin of moderator

1350–1400; Middle English <Latin moderātor, equivalent to moderā() to control (see moderate) + -tor-tor

OTHER WORDS FROM moderator

mod·er·a·to·ri·al [mod-er-uh-tawr-ee-uhl, -tohr-], /ˌmɒd ər əˈtɔr i əl, -ˈtoʊr-/, adjectivemod·er·a·tor·ship, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

How to use moderator in a sentence

British Dictionary definitions for moderator

moderator
/ (ˈmɒdəˌreɪtə) /

noun

Derived forms of moderator

moderatorship, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for moderator

moderator
[ mŏdə-rā′tər ]

A substance, such as graphite, water, or heavy water, placed in a nuclear reactor to slow neutrons down to speeds at which they are more likely to be captured by fissionable components of a fuel (such as uranium-235) and less likely to be absorbed by nonfissionable components of a fuel (such as uranium-238). Also called neutron moderator See also slow neutron.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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