Split tunneling - Definition from the Hotspot Shield Glossary
This is the process that allows a user to access a public network while still being connected to a VPN and its functionality. A public network could be a local area network, the internet or a wide area network.
Split tunneling is useful for providing increased network speeds and a boost in the flow of traffic - Instead of all the virtual network traffic flowing through one tunnel or path, the public aspects can be split out thus reducing the strain on the main network. For example, an employee might be accessing their companies network via a VPN - Using a split tunnel, they will be able to access the internet using their home broadband connection, and access their business files using the VPN network.