The Collaborative International Dictionary of English v.0.48:

Causerie \Cause`rie"\, n. [F., fr. causer to chat.]
   Informal talk or discussion, as about literary matters; light
   conversation; chat.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

causerie
    n 1: light informal conversation for social occasions [syn:
         chitchat, chit-chat, chit chat, small talk, gab,
         gabfest, gossip, tittle-tattle, chin wag, chin-
         wag, chin wagging, chin-wagging, causerie]