Router - Definition from the Hotspot Shield Glossary
A router is a device or software that is responsible for the forwarding packets of data onto the next point in a network. A router will be connected to two or more devices on a network and will send information on to the relative devices using an understanding of the network it is connected too.
Routing is performed at level 3 of the OSI reference model (The Network Layer) and a router will maintain a table that lists all the potential available routes data can travel, and use this to determine the quickest and most efficient path for data to be routed. A router can also act as a firewall in a network and protect the network against intrusions and hacking.
There are a wide range of routers available for purchase and nowadays they are inexpensive and easy to implement at a basic level of configuration.