Merriam-Webster's Collegiate® Dictionary, 11th Edition
MEDIATE
I. adjective
Etymology: Middle English, from Late Latin mediatus intermediate, from past participle of mediare
Date: 15th century
occupying a middle position,
2. acting through an intervening agency, exhibiting indirect causation, connection, or relation, mediacy noun mediately adverb
II. verb (-ated; -ating)
Etymology: Medieval Latin mediatus, past participle of mediare, from Late Latin, to be in the middle, from Latin medius middle
Date: 1568
transitive verb
1. to bring accord out of by action as an intermediary, to effect by action as an intermediary,
2. to act as intermediary agent in bringing, effecting, or communicating ; convey , to transmit as intermediate mechanism or agency, intransitive verb to interpose between parties in order to reconcile them, to reconcile differences, see: interpose mediative adjective mediatory adjective