A network adapter is a hardware component that allows a computer or device to connect to a network, enabling communication with other devices. It can be wired, like an Ethernet adapter, or wireless, such as a Wi-Fi adapter. Network adapters convert data into a format suitable for transmission over the network and vice versa. These adapters can be built into the device or added externally via USB or other ports. They play a crucial role in connecting devices to the internet or local networks, facilitating activities like browsing the web, streaming, and file sharing.