English Reference
noun

moderator

n.
US /ˈmɑdɝˌeɪtɝ/ UK /mˈɒdəɹˌeɪtɐ/ mod·er·a·tor UK spelling moderators

  1. 01 B2 Upper Intermediate Informal Computing

    a person who manages an online forum or social media group to make sure people follow the rules.

    an individual responsible for monitoring and managing content within an online community or social media platform to ensure compliance with terms of service.

    Simple

    The moderator removed the rude comments from the discussion board.

    In context

    Volunteer moderators often face the difficult task of balancing free speech with the need to prevent harassment in large digital communities.

  2. 02 B2 Upper Intermediate

    a person who leads a public discussion or debate to make sure it stays fair and organized.

    a neutral participant who presides over a debate or panel discussion to regulate the flow of conversation and enforce time limits.

    Simple

    The moderator asked both candidates to stop talking when their time was up.

    In context

    A skilled moderator can steer a heated political debate back toward substantive issues when the participants begin to trade personal insults.

  3. 03 C1 Advanced British EnglishFormal

    a person who checks that different teachers are marking exams in the same fair way.

    an official who monitors the marking of examinations by different examiners to ensure consistency and adherence to national standards.

    Simple

    The external moderator reviewed the students' essays to check the grades were fair.

    In context

    After the initial marking phase, a moderator was appointed to resolve the discrepancies between the two internal assessors' scores.

  4. 04 C2 Proficiency Technical Science

    a substance, like water or graphite, used in a nuclear reactor to slow down particles.

    a medium used in a nuclear reactor to reduce the velocity of fast neutrons, thereby increasing the probability of further fission reactions.

    Simple

    Graphite is often used as a moderator in certain types of nuclear power plants.

    In context

    The reactor's design relies on heavy water acting as a moderator to maintain a stable and controlled chain reaction.

  5. 05 C2 Proficiency Formal Religion

    the person in charge of a meeting or group in the Presbyterian church.

    the presiding officer of a synod or general assembly within the Presbyterian ecclesiastical tradition.

    Simple

    The Moderator of the General Assembly opened the meeting with a prayer.

    In context

    Each year, the synod elects a new moderator to oversee the administrative and spiritual functions of the regional church body.

    presiding officer

In the since-deleted video, the 70-year-old actor-filmmaker is seen walking out to cheers from the audience after moderator Liam Crowley introduces Gibson at the event held Saturday.

Toronto Sun· 31 Aug 2026

Learned borrowing from Latin moderātor. First attested as Middle English moderatour. By surface analysis, moderate + -or.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Middle English moderatour
Level B2 · Upper Intermediate
Frequency Frequent
Updated