moderator Meaning, Definition & Usage

  1. noun any substance used to slow down neutrons in nuclear reactors
  2. noun in the Presbyterian church, the officer who presides over a synod or general assembly
  3. noun someone who presides over a forum or debate
  4. noun someone who mediates disputes and attempts to avoid violence

WordNet

Mod"er*a`tor noun
Etymology
L.: cf. F. modérateur.
Definitions
  1. One who, or that which, moderates, restrains, or pacifies. Sir W. Raleigh.
    Angling was ... a moderator of passions. Walton.
  2. The officer who presides over an assembly to preserve order, propose questions, regulate the proceedings, and declare the votes.
  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.
  4. A mechamical arrangement for regulating motion in a machine, or producing equality of effect.

Webster 1913