It's a switch. The basic difference between a router and a switch is that a switch connects devices that are on the same network (LAN), and a router connects multiple networks together (like connecting the computers on your home LAN to your ISP's network, which then has their own routers connected to the many routers of the internet). Your typical SOHO router is actually a router and a switch in 1 box...the LAN ports are switch ports. A SOHO wireless router is a router, switch, and wireless access point in 1 box.
I'm guessing that should answer your question, but there is a lot more to switching and routing than that, so please ask if you have more detailed questions.