ELI5: Explain Like I'm 5

Expansion card

An expansion card is like a Lego block that you can add to your computer to make it do new and different things. Just like how you can add different Lego pieces to your creation to change it up, you can add an expansion card to your computer to change what it can do.

For example, let's say you want to play fancy video games on your computer, but it doesn't have the power to do that. You might add an expansion card that has a special chip on it to help your computer process graphics faster. Or, let's say you want to connect to the internet using Wi-Fi instead of a cable. You could add an expansion card that has a little antenna sticking out of it to help your computer connect to Wi-Fi.

Expansion cards are really cool because they let you customize your computer to do exactly what you want it to do. They are easy to install—you just need to slide them into a special slot inside your computer's tower—and they usually come with instructions to help you do it yourself.