What is the difference between a wireless access point and a bridge? I have a wireless router downstairs and a wireless router/access point upstairs in my office. I want to connect the desktop in my office to the router/access point via a ethernet cable, and have that router recieve the wireless signal from the router that's connected to the modem in the basement. What is this configuration called?
AP: A wireless infrastructure device that clients connect to for access to a larger network.
Bridge: Connecting two wired segments via Wireless APs (that's the practical definition at least). Wireless devices marketed as "bridges" are typically just stripped down access points.
What you describe doing in your house is a Bridge using two Access points. It should be possible, pending the router in your office can be set to a bridge mode where it can Join an existing wireless network like a normal client.
An Access Point may have capacities above a true network bridge, such as various levels of network authentication or VLAN trunking ability, but the kind you're likely to run into in the home are pretty much network bridges. They just link two different media types together onto the same logical network. The router-with-wifi devices just have this built into the router, but stand-alone access points are still available (I use one at home for a dead spot).
What you're looking to create is generally called a wireless bridge. The network diagram is roughly...
The two router/APs are configured to be a wireless bridge between two wired networks. Some devices can also still function as a regular access-point in this config, but I don't know how common that is.