con·cil·i·ate / kənˈsilēˌāt/ • v. [tr.] 1. stop (someone) from being angry or discontented; placate; pacify. ∎  [intr.] act as a mediator. ∎ formal reconcile; make compatible: all complaints about charges will be conciliated if possible.2. archaic gain (esteem or goodwill).DERIVATIVES: con·cil·i·a·tion / kənˌsilēˈāshən/ n.con·cil·i·a·tive / -ˈsilēətiv; -ēˌātiv/ adj.con·cil·i·a·tor / -ˌātər/ n.

conciliate gain the goodwill of, win over; reconcile. XVI. f. pp. stem of L. conciliāre unite, procure, win, f. concilium COUNCIL; see -ATE 3.
So conciliation, conciliator, conciliatory XVI.