reciprocity
The feature of mutual interaction, for example, in a relationship between people.
There might be benefit on one side, and obligation on the other; but their reciprocity of affection, their mutual exchange of small kindnesses—those strongest rivets of common attachment—were no more.
A mutually interactive relationship.
A relation of mutual dependence or action or influence.
(grammar) A construction that involves two noun phrases where each of the participants occupies both the role of agent and patient with respect to the other.
(international law) The mutual exchange of rights, privileges or obligations between nations.
(psychology) The responses of individuals to the actions of others.