Someone who acts as an intermediate agent in a transaction or helps to resolve differences
He was employed by his brother as a mediator with Philip the Fair in 1293-1294.
If you want a mediator, let me know.
One of these children is often his mediator with men, and has the charge of the rites and the mystic bull-roarer.
As queen-mother she played the part of a mediator between her sons and political parties.
She became the mediator between the Lombards and the Catholic Church.