Okay, kiddo, so a long time ago, there was a group of people called Jews who lived in a place called Israel. But then, some bad guys invaded Israel and took over the land. The Jews had to leave their homes and go live in other places where they were allowed to live.
This moving of the Jews from their homeland to other parts of the world is called the Jewish Diaspora. It's a big word that means the scattering of the Jewish people.
Over many centuries, Jews moved to different parts of the world like Europe, Africa, Asia, and the Americas, and they made new homes where they could live and practice their religion. Even today, there are Jewish communities all around the world.
So, that's what the Jewish Diaspora is all about, kiddo. The Jews had to leave their home in Israel and move to different parts of the world, but they still kept their traditions and beliefs and made new homes for themselves wherever they went.