ELI5: Explain Like I'm 5

Post-it note

A post-it note is a little piece of paper that has a sticky part on one side. It's like a tiny sticker that you can stick on anything you want. You can use it to write yourself a reminder, like "brush your teeth," or you can stick it on your friend's desk to leave them a message. When you're done with it, you just peel it off and throw it away. It's like a mini writing pad that you can carry with you wherever you go. People use post-it notes a lot in offices and schools to help them remember things or to communicate with each other.