Bittorrent is a way for people to share big files like movies, music, and pictures with each other over the Internet.
Let's say you want to download a movie that's really popular and lots of people want to download it at the same time. Instead of downloading the whole thing from just one person's computer, which would be really slow, you can download bits of the movie from lots of different people's computers all at the same time.
To do this, you need a special program called a bittorrent client. This program helps your computer talk to other computers and lets you download pieces of the movie from each of them. Each little piece that you download from someone's computer is called a "torrent."
Once your bittorrent client has downloaded all of the little torrents from different computers, it puts them all together into one big file - like a puzzle that you've finished. And then, voila! You have the full movie on your computer, ready to watch.
That's the basic idea behind bittorrent - it's a way for people to share big files with each other, making the download process faster and more efficient.