From The Collaborative International Dictionary of English v.0.48 :
Two-way \Two"-way`\, a. (Pipe Fitting)
Serving to connect at will one pipe or channel with either of
two others; as, a two-way cock.
[Webster 1913 Suppl.]
From WordNet (r) 2.0 :
two-way
adj 1: supported by both sides; "a two-way treaty" [syn: bipartisan,
bipartizan, two-party]
2: involving two parties or elements; "a bipartite document";
"a two-way treaty" [syn: bipartite, two-party]
3: operating or permitting operation in either of two opposite
directions; "a two-way valve"; "two-way traffic"; "two-way
streets"