Longman Dictionary of Contemporary English
Wiktionary
n. (context idiomatic English) A social interaction in which both parties are expected to give and take equally.
WordNet
n. a street on which vehicular traffic can move in either of two directions; "you have to look both ways crossing a two-way street"
Wikipedia
A two-way street is a street that allows vehicles to travel in both directions. On most two-way streets, especially main streets, a line is painted down the middle of the road to remind drivers to stay on their side of the road. Sometimes one portion of a street is two-way, the other portion one-way. If there is no line, a car must stay on the appropriate side and watch for cars coming in the opposite direction and prepare to pull over to let them pass.
Usage examples of "two-way street".
In humans loyalty is a two-way street, and the hive gave none of the emotional return humans require above such physical things as nutrition.
And the direct neuron interface with the jumpjet was a two-way street.