Hub - a hub connects computers or other devices to the network. all devices on the hub are in one CSMA/CD collision domain. called a MAU or MSAU on Token Ring networks. a hub provides network path between network devices
as you can see on this picture. the image shows a hub. typically a hub will have an incoming port and then other ports where you can distribute and share the incoming connection
you can use a hub at home if you have multiple computers and one dsl line, that way all your computer at home will have an internet connection