1.  moderator(n = noun.substance) - any substance used to slow down neutrons in nuclear reactors;
is a kind of inhibitor
is a part of nuclear reactor, reactor
has particulars: deuterium oxide, heavy water

2.  moderator(n = noun.person) - in the Presbyterian church, the officer who presides over a synod or general assembly;
is a kind of presiding officer
Derived form noun moderatorship₁

3.  moderator(n = noun.person) - someone who presides over a forum or debate;
is a kind of presiding officer
Derived forms verb moderate₁, noun moderatorship₁

4.  moderator(n = noun.person) - someone who mediates disputes and attempts to avoid violence;
is a kind of go-between, intercessor, intermediary, intermediator, mediator
has particulars: modifier
Derived forms verb moderate₆, noun moderatorship₁

1.  One who, or that which, moderates, restrains, or pacifies. Sir W. Raleigh. [1913 Webster]
"Angling was . . . a moderator of passions." [1913 Webster]

2.  The officer who presides over an assembly or discussion to preserve order, propose questions, regulate the proceedings, and declare the votes. [1913 Webster]

3.  In the University of Oxford, an examiner for moderations; at Cambridge, the superintendant of examinations for degrees; at Dublin, either the first (senior) or second (junior) in rank in an examination for the degree of Bachelor of Arts. [1913 Webster]

4.  A mechanical arrangement for regulating motion in a machine, or producing equality of effect. [1913 Webster]

moderator, n.
1 an arbitrator or mediator.
2 a presiding officer.
3 Eccl. a Presbyterian minister presiding over an ecclesiastical body.
4 an examiner for Moderations.
5 Physics a substance used in a nuclear reactor to retard neutrons.

Derivative:
moderatorship n.

Etymology:
ME f. L (as MODERATE)

N  director, manager, governor, rector, comptroller, superintendent, supervisor, straw boss, intendant, overseer, overlooker, supercargo, husband, inspector, visitor, ranger, surveyor, aedile, moderator, monitor, taskmaster, master, leader, ringleader, demagogue, corypheus, conductor, fugleman, precentor, bellwether, agitator, caporal, choregus, collector, file leader, flugelman, linkboy, guiding star, adviser, guide, pilot, helmsman, steersman, steermate, wire-puller, driver, whip, Jehu, charioteer, coachman, carman, cabman, postilion, vetturino, muleteer, arriero, teamster, whipper in, head, head man, head center, boss, principal, president, speaker, chair, chairman, chairwoman, chairperson, captain, superior, mayor, vice president, prime minister, premier, vizier, grand vizier, eparch, officer, functionary, minister, official, red-tapist, bureaucrat, man in office, Jack in office, office bearer, person in authority, statesman, strategist, legislator, lawgiver, politician, statist, statemonger, Minos, Draco, arbiter, boss, political dictator, board, secretary, secretary of state, Reis Effendi, vicar, steward, factor, agent, bailiff, middleman, foreman, clerk of works, landreeve, factotum, major-domo, seneschal, housekeeper, shepherd, croupier, proctor, procurator, ex officio.

N  mediation, mediatorship, mediatization, intervention, interposition, interference, intermeddling, intercession, arbitration, flag of truce, good offices, peace offering, parley, negotiation, diplomatics, diplomacy, compromise, mediator, arbitrator, intercessor, peacemaker, makepeace, negotiator, go-between, diplomatist, moderator, propitiator, umpire, mediatory.

N  moderation, lenity, temperateness, gentleness, sobriety, quiet, mental calmness, moderating, anaphrodisia, relaxation, remission, mitigation, tranquilization, assuagement, contemporation, pacification, measure, juste milieu, golden mean, ariston metron, moderator, lullaby, sedative, lenitive, demulcent, antispasmodic, carminative, laudanum, rose water, balm, poppy, opiate, anodyne, milk, opium, poppy or mandragora, wet blanket, palliative, moderate, lenient, gentle, mild, mellow, cool, sober, temperate, reasonable, measured, tempered, calm, unruffled, quiet, tranquil, still, slow, smooth, untroubled, tame, peaceful, peaceable, pacific, halcyon, unexciting, unirritating, soft, bland, oily, demulcent, lenitive, anodyne, hypnotic, sedative, antiorgastic, anaphrodisiac, mild as mother's milk, milk and water, moderately, gingerly, piano, under easy sail, at half speed, within bounds, within compass, in reason, est modue in rebus, pour oil on troubled waters.

N  luminary, light, flame, spark, scintilla, phosphorescence, fluorescence, sun, orb of day, Phoebus, Apollo, Aurora, star, orb, meteor, falling star, shooting star, blazing star, dog star, Sirius, canicula, Aldebaran, constellation, galaxy, zodiacal light, anthelion, day star, morning star, Lucifer, mock sun, parhelion, phosphor, phosphorus, sun dog, Venus, aurora, polar lights, northern lights, aurora borealis, southern lights, aurora australis, lightning, chain lightning, fork lightning, sheet lightning, summer lightning, ball lightning, kugelblitz, phosphorus, yellow phosphorus, scintillator, phosphor, firefly luminescence, ignis fatuus, Jack o'lantern, Friar's lantern, will-o'-the- wisp, firedrake, Fata Morgana, Saint Elmo's fire, glowworm, firefly, June bug, lightning bug, anglerfish, gas, gas light, lime light, lantern, lanthorn, dark lantern, bull's-eye, candle, bougie, taper, rushlight, oil, wick, burner, Argand, moderator, duplex, torch, flambeau, link, brand, gaselier, chandelier, electrolier, candelabrum, candelabra, girandole, sconce, luster, candlestick, lamp, light, incandescent lamp, tungsten bulb, light bulb, flashlight, torch, arc light, laser, maser neon bulb, neon sign, fluorescent lamp, filament, socket, contacts, filler gas, firework, fizgig, pyrotechnics, rocket, lighthouse, self-luminous, glowing, phosphoric, phosphorescent, fluorescent, incandescent, luminescent, chemiluminescent, radiant, blossomed the lovely stars, the forget-me-nots of the angels, the sentinel stars set their watch in the sky, the planets in their station list'ning stood, the Scriptures of the skies, that orbed continent, the fire that severs day from night.