mediate (v.)

1540s, "divide in two equal parts" (a sense now obsolete), from Latin mediatus, past participle of mediare "to halve," later, "be in the middle," from Latin medius "middle" (from PIE root *medhyo- "middle"); from 1640s as "occupy a middle place or position." Meaning "act as a mediator, intervene for the purpose of reconciliation" is from 1610s; that of "settle by mediation, harmonize, reconcile" is from 1560s, perhaps back-formations from mediation or mediator. Related: Mediated; mediates; mediating.

early 15c., "intermediate," from Medieval Latin mediatus, past-participle adjective from Latin mediare "to be in the middle," from medius "middle" (from PIE root *medhyo- "middle"). Related: Mediately.