A network interface controller, or NIC for short, is a very important piece of equipment in computers that helps them to connect to the internet. Picture it like a special conductor that helps the computer talk to other devices on the internet, like a teacher helping you communicate with your classmates. It's a small card that fits inside your computer and plugs into the motherboard, like a puzzle piece fitting in a puzzle.
Once the NIC is plugged in, it can connect to the internet either through wires or through wireless technology (like WiFi). This allows your computer to send and receive information to other devices on the internet, like when you send an email or watch a video on YouTube. The NIC also has the job of translating the information that comes in and out of your computer so it can understand it properly.
Without a NIC, your computer wouldn't be able to connect to the internet at all and you wouldn't be able to do anything online. So next time you're surfing the web, thank your NIC for helping you get connected!