In this manual, the term “argument” refers to the entity that is passed to a function. In some cases, it is modified by “actual” or “formal,” which mean the argument expression specified in the function call and the argument declaration specified in the function definition, respectively.
The term “variable” refers to a simple C-type data object. The term “object” refers to both C++ objects and variables; it is an inclusive term.
For more information on terminology, see Terms.