A "Bridge" is a LAN term to connect (bridge) 2 separate networks together. You'd think, "Wouldn't this 'bridge' just be a router? It could be a router to connect the networks but the router, in this case, would be called a Gateway.
The difference between a Bridge and a Router is the addresses each uses to...for lack of a better term...route traffic. Routers use IP addresses to route and Bridges use MAC addresses.
FYI: A MAC address is programmed into the NIC by its manufacturer. A MAC address should be permanent but some manufacturers allow it to be programmable or changed.
In this case, you have a combo modem-router. The Cox network terminates at the modem portion of this combo device and then transfers traffic to router portion. It's all internally transferred so you have no access to it.
If you wanted to troubleshoot (or use a better router), you could turn off the router portion of this combo device. Meaning...you don't want the router to assign IP addresses or route anything...but instead to just transfer the traffic from the modem to whatever is connected to the router portion, such as another router or computer.
Since traffic will still be traveling through the router portion, the router, in this case, is just "bridging" the traffic onto your network (the other router) and staying at Layer-2 of the networking protocol. The other router would be Layer-3 (IP addresses).
Bottom line. There are 2 networks involved: the Cox network (modem) and your personal, private, home network (router). The Pano is your private network because it controls all your devices connected to it either wired or wireless. If you didn't want the Pano to control your home network, you could put it into Bridge Mode to just transfer all traffic to/from the modem to whatever would be your home network.