mediate (v.) Look up mediate at Dictionary.com
1540s, "divide in two equal parts," probably a back-formation from mediation or mediator, or else from Latin mediatus, past participle of mediare "to halve," later, "be in the middle," from Latin medius "middle" (see medial (adj.)). Meaning "act as a mediator" is from 1610s; that of "settle by mediation" is from 1560s. Related: Mediated, mediates, mediating.