one who, or that which, moderates, restrains, or pacifies.-the officer who presides over an assembly to preserve order, propose questions, regulate the proceedings, and declare the votes.-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.-a mechamical arrangement for regulating motion in a machine, or producing equality of effect.