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.
Origin of moderator
1350–1400;Middle English < Latinmoderātor, equivalent to moderā(rī) to control (see moderate) + -tor-tor
Related formsmod·er·a·to·ri·al[mod-er-uh-tawr-ee-uh l, -tohr-]/ˌmɒd ər əˈtɔr i əl, -ˈtoʊr-/, adjectivemod·er·a·tor·ship, noun
Presbyterian Churcha minister appointed to preside over a Church court, synod, or general assembly
a presiding officer at a public or legislative assembly
a material, such as heavy water or graphite, used for slowing down neutrons in the cores of nuclear reactors so that they have more chance of inducing nuclear fission
an examiner at Oxford or Cambridge Universities in first public examinations
(in Britain and New Zealand) one who is responsible for consistency of standards in the grading of some educational assessments
a person who monitors the conversations in an on-line chatroom for bad language, inappropriate content, etc
late 14c., "ruler, governor," from Latin moderator "manager, ruler, director," literally "he who moderates," from moderatus (see moderate (adj.)). Meaning "one who acts as an umpire" is from 1560s. Fem. form moderatrix attested from 1530s.
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.
