What term refers to special variables used to pass values into a subprogram?

The term that refers to special variables used to pass values into a subprogram is parameters. Parameters are defined in the subprogram's function or method definition and act as placeholders for the actual values, known as arguments, that will be provided when the subprogram is called. This allows for more flexible and reusable code, as the same subprogram can be executed with different values each time it is called.

In contrast, arguments refer to the actual values that are passed to the subprogram when it is invoked. While the terminology may seem similar, parameters specifically denote the variables in the subprogram definition, whereas arguments are the concrete data supplied during execution. Variables, in general context, can refer to any named storage location in programming, and attributes typically pertain to characteristics of objects in object-oriented programming, which do not directly relate to passing values into subprograms.