sim·plex / ˈsimpleks/ • adj. technical composed of or characterized by a single part or structure. ∎  (of a communications system, computer circuit, etc.) only allowing transmission of signals in one direction at a time.• n. a simple or uncompounded word.

simplex
1. Denoting or involving a connection between two endpoints, either physical or logical, that can carry data in only one direction with no possibility of data flow in the opposite direction. See also duplex, half duplex.

2. A finite graph of k points (the vertices), or a geometric figure, in which every vertex is connected to every other vertex (e.g. a triangle or tetrahedron).