mediation

from The Century Dictionary.

• noun The act of mediating; intervention; interposition.
• noun Agency between parties with a view to reconcile them or to effect some arrangement between them; entreaty for another; intercession.
• noun The state of being mediate, or of serving as a medium or means; intermediate relation; a coming between.
• noun Means; aid; help.
• noun In music: In Gregorian music, that part of a melody which lies between the intonation and the ending—that is, the main part of the melody.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act of mediating; action or relation of anything interposed; action as a necessary condition, means, or instrument; interposition; intervention.
• noun Hence, specifically, agency between parties at variance, with a view to reconcile them; entreaty for another; intercession.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun negotiation to resolve differences conducted by some impartial party.
• noun the act of intervening for the purpose of bringing about a settlement.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the act of intervening for the purpose of bringing about a settlement
• noun a negotiation to resolve differences that is conducted by some impartial party