What keyword is used to define a class in PHP?

The keyword used to define a class in PHP is "class." When you want to create a new class, you begin with this keyword followed by the name of the class. This structure allows you to encapsulate properties and methods that define the behavior and attributes of objects created from the class.

For example, the following code snippet demonstrates how to define a basic class in PHP:

class MyClass {
    public $property;

    public function myMethod() {
        // method code
    }
}

In this example, "class" is utilized to initiate the class definition, "MyClass" is the name of the class, and it includes a property and a method. This is foundational in object-oriented programming and enables the creation of complex applications by structuring code into reusable components.

The other options do not fulfill this purpose: "define" is used for defining constants, "function" is used for declaring functions, and "object" refers to instances of classes rather than the definition of the class itself. Understanding the role of "class" is crucial when working with object-oriented principles in PHP.