In general, a Hub is a central node in a network. The term comes from the analogy to a wheel's hub, the center.

A hub is a computer networking device that connects multiple Ethernet segments together making them act as a single segment. When using a hub only one computer connected to the hub is able to transmit at a time.

With a hub every attached device shares the same broadcast domain and the same collision domain.

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: Bicycle wheel for information about bicycle wheel hub, Spoke-hub distribution paradigm