A cultural exchange or cultural interchange was a broad term given to any mutual sharing of information, usually cultural, between two or more species for the purpose of improving friendship and understanding between them.
In the 2340s, Devinoni Ral successfully brokered a cultural exchange between his university, the University of Hurkos, and the Orion University. This event was mentioned in Ral's biographical data file. (TNG: "The Price")
In 2368, Jean-Luc Picard proposed signing a nonaggression pact with the Tamarians, "possibly leading to a trade agreement and cultural interchange" but Dathon was unable to understand what he said. (TNG: "Darmok")
Some examples of cultural exchange included the Interspecies Medical Exchange, the Galactic Cultural Exchange Project, the Officer Exchange Program, and the visits made by Jean-Luc Picard and the Iyaarans in 2370. (TNG: "Liaisons")