From the standpoint of a computer data network, a network interface is a component that contains all the hardware required to physically connect a computing device to the network. The network interface card could connect a computing device to an ethernet, token-ring, FDDI, SONET, or wireless wi-fi or bluetooth network.
You connnect a network interface to a network segment to attach it to the network. When connected to form a network, the segments are said to be laid out in a bus, ring, star or daisy-chain topology.