A NIC Card is a piece of hardware in a computer that allows the computer to connect to and communicate with a network, other computers or the Internet.
This hardware is also commonly referred to as an Ethernet Card, Network Card, Network Adapter or a LAN Adapter. Ethernet Cards may be installed as a separate card in the computer or they may be embedded in the motherboard by the manufacturer. Your computer can not connect to a network without having an Ethernet interface.