A wireless router is a device that performs the functions of a router and also includes the functions of a wireless access point. It is used to provide access to the Internet or a private computer network. Depending on the manufacturer and model, it can function in a wired local area network, in a wireless-only LAN, or in a mixed wired and wireless network.
Most current wireless routers have the following characteristics:

One or multiple NICs supporting Fast Ethernet or Gigabit Ethernet integrated into the main SoC
One or multiple WNICs supporting a part of the IEEE 802.11-standard family also integrated into the main SoC or as separate chips on the printed circuit board. It also can be a distinct card connected over a MiniPCI or MiniPCIe interface.