Source : Webster's Revised Unabridged Dictionary (1913)

Three-way \Three"-way`\, a.
   Connected with, or serving to connect, three channels or
   pipes; as, a three-way cock or valve.

Source : WordNet®

three-way
     adj : involving three parties or elements; "the triangular
           mother-father-child relationship"; "a trilateral
           agreement"; "a tripartite treaty"; "a tripartite
           division"; "a three-way playoff" [syn: {triangular}, {trilateral},
            {tripartite}, {three-party}]