What keyword is used to define a class in C++?

The keyword used to define a class in C++ is indeed "class." In C++, a class serves as a blueprint for creating objects, encapsulating data and functions that operate on that data.

When defining a class, using the "class" keyword allows you to establish the structure and behavior of the objects that will be instantiated from it. For example, the syntax involves using "class ClassName" followed by the class body enclosed in braces, where you can specify member variables and member functions that define the characteristics and behaviors of the class.

The other keywords mentioned do have specific uses in C++, but they do not serve to define a class. "struct" is similar to "class," as it can also define a custom data type, but with default public access for its members. "define" is not a keyword in C++; rather, "define" refers to a preprocessor directive for macros (using #define) and is unrelated to class definitions. Lastly, "object" refers to an instance of a class, not the class itself. Therefore, the "class" keyword is the correct choice for defining a class in C++.