Well kiddo, let's start with the basics. Ireland and the Caribbean are two places in the world that are really far apart. Ireland is a small island in Europe, while the Caribbean is a group of islands in the Caribbean Sea.
Now, when people talk about the "Irish Caribbean," they are usually referring to a historical connection between Irish people and the Caribbean.
You see, a long time ago, Ireland was ruled by England (which is another country in Europe). During this time, many Irish people were forced to leave their homes and go to other places. Some of them went to the Caribbean, where they became indentured servants or slaves.
Being an indentured servant or slave meant that you had to work really hard for someone else without getting paid much (or at all). It was a really tough life.
Over time, some of these Irish people started to form communities in the Caribbean. They brought some of their traditions and culture with them, like their music and their religion (which was usually Catholic).
Today, you can still see some of this Irish influence in the Caribbean. For example, there is a famous music style called "calypso" that has roots in Ireland. And in some parts of the Caribbean, people still celebrate St. Patrick's Day (which is a holiday that originated in Ireland).
So that's the "Irish Caribbean" in a nutshell, kiddo. It's a connection between two places that goes back a long time and has left an impact on both.