[idi banashapan]

An access point will act as a wireless point for your devices to connect to, and transmit data too and from the router it is plugged in to via a wire. It's like a wireless extender in principle (i.e., it means you can use wireless without needing to be near the router), but uses a different method.

A wireless extender, or repeater, will pick up the existing wireless signal and amplify it so that devices out of the normal range for the main wireless hub can get a signal.

An Access point has no dependency on an existing wireless signal - so long as it is attached to the router / switch / network via a wire, you can set up a wireless access point anywhere. If you wanted to, and the wire was long enough (but still within usable limits), you could run a cable to next door with an AP on the end of it and they could connect to your network if you gave them the credentials. Any old router you have still laying around will likely be able to perform the task for you, however you can buy dedicated AP units.