Sharing video signals is the key reason for a video distribution system. An integral part of successfully sharing those signals is the splitter.
Splitters do exactly what it sounds like - they take one set of signals, and distribute them to multiple connections. Splitters are available in both active and passive versions. Active splitters add amplification to the incoming signal, so the signal does not suffer from signal loss after splitting. Passive splitters will cause a drop in signal after splitting. For proper signal strength, signal that will be routed through a passive splitter may need amplification prior to splitting.