Someone or something that introduces.
Someone who moderates.
An arbitrator or mediator.
The person who presides over a synod of a Presbyterian Church.
A substance (often water or graphite) used to decrease the speed of fast neutrons in a nuclear reactor and hence increase likelihood of fission.
The chair or president of a meeting, etc.
An examiner at Oxford and Cambridge universities.
Someone who supervises and monitors the setting and marking of examinations by different people to ensure consistency of standards.
A kind of lamp in which the flow of the oil to the wick is regulated.
At the University of Dublin, either the first (senior) or second (junior) in rank in an examination for the degree of Bachelor of Arts.
A mechanical arrangement for regulating motion in a machine, or producing equality of effect.
A person who enforces the rules of a discussion forum by deleting posts, banning users, etc.
A device used to deaden some of the noise from a firearm, although not to the same extent as a suppressor or silencer.