Why does the function arguments are called as "signatures"?

The arguments distinguish functions with the same name (functional polymorphism). The name alone does not necessarily identify a unique function.  However, the name and its arguments (signatures) will uniquely identify a function.

            In real life we see suppose, in class there are two guys with same name, but they can be     easily identified by their signatures. The same concept is applied here.

            ex:

                        class person

                        {

                  public:

                                    char getsex();

                                    void setsex(char);

                                    void setsex(int);

                        };

            In the above example we see that there is a function setsex() with same name but with different signature.