When you create a class, you create "instances" or "objects" of the class. Each object has the same number of variables and each variable is named the same, but they have different data.
For example, all cars have a color, a model, and a certain number of seats, but each car differs in these characteristics. One car may be red, another may be blue, but they all have a color. The "idea" of a car would be the class, and each individual car would be an object or instance of the class.
This is called Object-Oriented Programming. It's not unique to PHP. Many languages use this.
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