(n.) Mutual communication.

ESP agglomeration agglutination aggregation alternation answer articulation bond bracketing clustering coaction collegiality combination commerce communication communion community complementary distribution concatenation concourse concurrence confluence congeries conglomeration congress conjugation conjunction connection contact convergence conversation converse cooperation copulation correspondence coupling dealing dealings engagement exchange fellowship gathering hookup information interaction interchange intercommunion intercourse interlacing interlinking intermeshing interplay intertwining interweaving interworking joinder joining jointure junction knotting liaison linguistic intercourse linkage linking marriage meeting merger merging mesh meshing message pairing quid pro quo reply response seesaw social activity social intercourse social relations speaking speech speech circuit speech situation splice symbiosis talking telepathy tie tie-in tie-up tit for tat touch traffic truck two-way communication unification union yoking