Adevice that makes it possible for multiple customers to share one address is called a/n
nat
wlan
dsl
url

When you use the word "address", I assume you are referring to an external address, in which case the answer is NAT (network address translation). Essentially, network address translation converts LAN IP addresses (local IP addresses) to WAN  IP addresses (external IP addresses). So for instance: everyone in my home accesses the internet under our network's external IP address. Inside our network, we have local IP addresses, which allow for packets to be routed to our individual machines wirelessly. So let's say my IP address on the LAN is 192.168.1.4, and I want to access brianly.com. My router performs NAT by converting my local IP to an external one which can be used for accessing the web. Then when data comes back to the network from 's server, my router once again performs NAT to convert between my external IP to my local IP, so that my router knows where the data needs to be routed to on the LAN.