When we talk about the meaning of a word or a sentence, we're talking about what it's trying to say or communicate. Imagine you're playing a game with your friends and you pick up a card that has a picture of a cat on it. The word "cat" is written at the bottom of the picture. When you look at that picture and see the word "cat," you understand that it's talking about a furry animal with pointy ears and whiskers. That's the meaning of the word "cat."
But sometimes, it's not always that simple. Sometimes words can have multiple meanings, or they can be used in ways that don't always make sense. For example, if I said "I'm feeling blue," you might think I mean that I'm actually the color blue. But of course, that's not what I mean. In this case, "blue" is being used as a way to describe a feeling—feeling sad or down. And even though "blue" doesn't actually mean "sad," we all understand what it means when it's used in that way.
So, the meaning of a word or a sentence is really about understanding what someone is trying to say, whether it's through pictures, words, or even body language. And sometimes, it's not always easy to understand, but the more we practice and learn, the better we can become at understanding the meaning of things.