In general, a hub is a centre point:

• a wheel's hub, which is the center of the wheel with spokes radiating out from it.
• a node in a network.
• a computer networking device that connects multiple Ethernet segments together making them act as a single segment. When using a hub, every attached device shares the same broadcast domain and the same collision domain. Therefore, only one computer connected to the hub is able to transmit at a time. Depending on the network topology, the hub provides a basic level 1 OSI model connection among the network objects (workstations, servers, etc). It provides bandwidth which is shared among all the objects, compared to switches, which provide a dedicated connection between individual nodes.
• see also Spoke-hub distribution paradigm
• a hub in computer games, is a set of levels that the player can travel back and forth. The levels aren't "restarted" each time, but they are left the same state as when player left them.
• an airline hub is an airport that serves as the base of operations for an airline, usually where most of its flights originate
• the hub is where an aircraft's propellers are attached
• A nickname for the city of Boston, Massachusetts. (From Oliver Wendell Holmes's phrase Hub of the Universe.)