Function: adjective
Date: 1844
1 : being a cock or valve that will connect a pipe or channel with either of two others
2 : moving or allowing movement in either direction <a two-way bridge>
3 a : involving or allowing an exchange between two individuals or groups <there must be good two-way communication ― Jerrold Orne> especially : designed for both sending and receiving messages < two-way radio> b : involving mutual responsibility or reciprocal relationships <political alliance is a two-way thing ― T. H. White † 1986>
4 : involving two participants <a two-way race>
5 : usable in either of two manners <a two-way lamp>