In C++, void is a keyword that has several uses. Here are some of them:

• Function return type: When used as a function return type, void specifies that the function doesnt return a value.
• Function parameter list: When used for a functions parameter list, void specifies that the function takes no parameters.
• Pointer declaration: When used in the declaration of a pointer, void specifies that the pointer is "universal." If a pointers type is void*, the pointer can point to any variable thats not declared with the const or volatile keyword. A void* pointer cant be dereferenced unless its cast to another type. A void* pointer can be converted into any other type of data pointer.
• Void pointers: void has a third, more advanced use in C++ that involves void pointers. Void pointers are pointers that can point to any type of data, but they cannot be dereferenced unless they are cast to another type.

In summary, void is used to indicate that a function does not return a value, that a function takes no parameters, or that a pointer is universal and can point to any type of data.