From The Collaborative International Dictionary of English v.0.48 :
Mediate \Me"di*ate\, v. i. [imp. & p. p. Mediated; p. pr. &
vb. n. Mediating.] [LL. mediatus, p. p. of mediare to
mediate. See Mediate, a.]
[1913 Webster]
1. To be in the middle, or between two; to intervene. [R.]
[1913 Webster]
2. To interpose between parties, as the equal friend of each,
esp. for the purpose of effecting a reconciliation or
agreement; as, to mediate between nations.
[1913 Webster]
From WordNet (r) 3.0 (2006) :
mediated
adj 1: acting or brought about through an intervening agency;
"the mediated settlement brought satisfaction to both
sides"