'Moderator' definitions:

Definition of 'moderator'

From: WordNet
noun
Any substance used to slow down neutrons in nuclear reactors
noun
In the Presbyterian church, the officer who presides over a synod or general assembly
noun
Someone who presides over a forum or debate
noun
Someone who mediates disputes and attempts to avoid violence

Definition of 'Moderator'

From: GCIDE
  • Moderator \Mod"er*a`tor\, n. [L.: cf. F. mod['e]rateur.]
  • 1. One who, or that which, moderates, restrains, or pacifies. --Sir W. Raleigh. [1913 Webster]
  • Angling was . . . a moderator of passions. --Walton. [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]