In data networking this term is defined as Signals may flow in either direction but not simultaneously?

The term you're referring to is "half-duplex." In a half-duplex communication system, signals can travel both ways between two devices, but only one device can send or receive data at a time. This means that while one device is transmitting, the other must wait until the transmission is complete before it can respond. Examples of half-duplex communication include walkie-talkies and traditional two-way radiOS.