U-matic is like a big and old video cassette. Think about it like a big book that you can put into a special machine that makes pictures and sounds. This machine is called a video player.
The U-matic tape is actually a big spool of thin film with little squares on it. These squares have pictures and sounds on them, kind of like a secret code that only the machine can understand.
The U-matic tape was very popular in the old days because it was one of the first video tapes that people could use to make movies and TV shows. People would use big cameras to record a show or movie on the U-matic tape, then they could put it into the video player and watch it on TV.
But now, we have new ways to make and watch movies and TV shows like using DVDs or streaming online. So people don't really use U-matic tapes anymore. But they are still important because they helped start the world of video recording and show us how far technology has come.