ˈmädəˌrād.ə(r), -rātə- noun
( -s )
Etymology: Middle English moderatour, from Latin moderator, from moderatus (past participle of moderare, moderari to moderate) + -or
1. : one that rules or directs : governor
act in his name as moderator of the Western realm — E.A.Freeman
2. : one who arbitrates : mediator
the governor persuaded both sides to continue their talks with the moderator — Springfield (Massachusetts) Union
3. : one who presides over an assembly, meeting, or discussion: as
a. : a presiding officer of any of various church meetings or assemblies within Protestant Christianity ; especially : the presiding officer elected within a Presbyterian polity to preside over a general assembly or over a smaller regional meeting
b. : an official presiding over the exercises formerly prescribed for candidates for an academic degree — now used of an examiner for moderations at Oxford as well as of one of the two officers presiding over the mathematical tripos at Cambridge
c. : the nonpartisan presiding officer of a town meeting
d. : a person who acts as chairman of a discussion group (as on radio or television)
4. archaic : a person or thing that moderates or calms
angling was … a moderator of passions — Izaak Walton
5.
a. : a member of a group opposed to the violent methods of the regulators in No. Carolina about 1770
b. : a member of one of numerous illegal bands active especially in Texas about the middle of the 19th century
6. : a candidate for the B.A. at Dublin taking first or second honors
7. : a substance (as graphite, deuterium in heavy water, or beryllium) used for slowing down neutrons in a nuclear reactor