What device allows a computer to connect to a network?

A Network Interface Card (NIC) is a crucial component that allows a computer to connect to a network. It can be integrated into the computer's motherboard or added as an expansion card. The NIC enables communication between the computer and other devices on the network by converting the data from the computer into a format suitable for transmission over the network media. This allows for both wired and wireless connections depending on the type of NIC used.

In contrast, while a switch is used to connect multiple devices within a local area network and manage data traffic effectively, it does not provide the initial connection for individual computers. A router, on the other hand, facilitates communication between different networks, such as linking a local network to the internet, but it requires devices like a NIC in order to interact with the local computers. Lastly, Ethernet refers to the technology used for wired networking, but it is not a component or device by itself; rather, it defines the protocol and physical connection method that the NIC uses to communicate.