Ogg Vorbis is a music file format that makes songs sound good and takes up less space on your computer or phone than other music file formats.
Think of it like building blocks - each song is made up of lots of different little pieces (called "bits") that tell your ears what sounds to hear. If those bits are really big and chunky, they take up a lot of space and your device has to work harder to process them, which can slow things down.
Ogg Vorbis takes those little pieces, breaks them down into even smaller pieces, and then puts them back together in a way that still sounds great, but takes up less space. So it's like using smaller, more efficient building blocks to make the same cool thing.
And the best part? Because Ogg Vorbis is an "open-source" format, which means anyone can use it for free, it's available for everyone to enjoy without paying extra fees or worrying about legal issues.