Pertaining to only one direction, e.g.: where all component parts are aligned in the same direction in space.
2005, Richard Samson, Training for the New Millennium: Pedagogies for translation and interpreting, edited by Martha Tennent, Benjamins Translation Library, p. 119:Equally important is the class mailing list, which facilitates two-way communication at a distance. (By contrast, the web page is basically a unidirectional teacher-to-student communication.)
