Interaction

n.	1.	Intermediate action.
	2.	Mutual or reciprocal action or influence; as, the interaction of the heart and lungs on each other.
	3.	(Physics) The effect, such as exertion of a force, that one object exerts on another, especially the capture or emission of a particle.
	4.	Communication between people, or the actions of people that affect others.

Noun	1.	interaction - a mutual or reciprocal action; interacting
	2.	interaction - (physics) the transfer of energy between elementary particles or between an elementary particle and a field or between fields; mediated by gauge bosons Synonyms: fundamental interaction

ESP, alternation, answer, coaction, commerce, communication, communion, complementary distribution, concurrence, congress, connection, contact, conversation, converse, cooperation, correspondence, dealing, dealings, engagement, exchange, information, interchange, intercommunication, intercommunion, intercourse, interlacing, intermeshing, interplay, intertwining, interweaving, interworking, linguistic intercourse, mesh, meshing, message, quid pro quo, reply, response, seesaw, social intercourse, speaking, speech, speech circuit, speech situation, talking, telepathy, tit for tat, touch, traffic, truck, two-way communication