The Collaborative International Dictionary of English v.0.48:

Rapport \Rap*port"\ (r[a^]p*p[=o]rt"; F. r[.a]`p[^o]r"), n. [F.,
   fr. rapporter to bring again or back, to refer; pref. re- re-
   + apporter to bring, L. apportare. Cf. Report.]
   Relation; proportion; conformity; correspondence; accord.
   [1913 Webster]

         'T is obvious what rapport there is between the
         conceptions and languages in every country. --Sir W.
                                                  Temple.
   [1913 Webster]

   En` rap`port" ([aum]N` r[.a]`p[^o]r") [F.], in accord,
      harmony, or sympathy; having a mutual, especially a
      private, understanding; in hypnotism, in that relation of
      sympathy which permits influence or communication.
      [1913 Webster]

WordNet (r) 3.0 (2006):

rapport
    n 1: a relationship of mutual understanding or trust and
         agreement between people [syn: rapport, resonance]