Okay kiddo, let me explain what a Unicode block is in a very simple way.
You know how we use different letters and symbols to write things down like letters, numbers, emojis and other stuff like that? Well, these letters and symbols are called characters.
Unicode is like a big library that has all the possible characters you could ever think of. And a Unicode block is like a group or category of characters that belong together because they have something in common, like being from the same language or having a similar appearance.
For example, there's a Unicode block called "Latin-1 Supplement" that has characters used in many European languages like French, German, and Spanish. Another Unicode block is "Emoticons" that has all those cute little pictures you see on your phone like smiley faces, hearts and thumbs up.
So, when we're talking about Unicode blocks, we're just talking about different groups of characters that are organized together to make it easier for people to find and use them.