hardware (or its representation by software) that connects a computing device (host) to a computer network (net)

A network interface controller (NIC) is a hardware component of a single computer (also known as, e.g., a device or host) that connects it to a network of other computers (also known as, e.g., a grid, mesh, or net). The representation of such hardware in operating systems and related applications (e.g., ifconfig) is also typically called an interface.