NIC – Network Interface Controller or Card or network adapter. This interfaces a computing device to a network, an Ethernet local area network for example. They were originally actual expansion cards that plugged into host system’s PCIe bus. Ethernet has become so ubiquitous that many motherboards now have built in NICs and no longer need expansion cards. The NIC provides an electrical connection to a wired or wireless network and handles the actual network physical layer and data link layer standards involved, such as Ethernet or Wi-Fi.