Lewis Short
mŏdĕrātrix (noun F) : moderator.
* She who moderates or allays; a directress, mistress, governess (mostly Ciceron.): sibi,Plaut. Cist. 2, 2, 3.
* That which rules, guides, controls, etc.: temperantia est moderatrix omnium commotionum,Cic. Tusc. 5, 14, 42: materiae,id. N. D. 3, 39, 92: factorum,id. Phil. 5, 18, 50: officii,id. Fl. 24, 57.
Charlton T. Lewis, Charles Short, A Latin Dictionary