trialogue

noun

1. (uncommon)A conversation or talk between three people.

   “Only for a short while was he kept waiting. The trialogue came to a close, followed by a brief interval of silence—at the end of which the canoe once more made its appearance upon the open water of the lagoon.”

   “If you knew how happy it made me that, whenever she interrupted his monopoly of you, instead of making a trialogue with them, you never failed to turn to me!”

2. (European-Union)An informal tripartite meeting attended by representatives of the European Parliament, the Council of the European Union, and the European Commission.