Implemtation of another class

public class PostGraduateStudent extends Student{

String researchGroup;
PostGraduate(String fn, String ln, Gender g, int nomr, String rg){
super(fn,ln,g,nomr);
researchGroup = rg;
}
public String toString(){
return super.toString() + "," + researchGroup;
}
}

public class Student{

enum Gender{MALE, FEMALE}
//{
String firstName;
String lastName;
Gender gender;
int noOfModulesRegistered;
//}
static double costOfModule = 756.90;

Student(String fn, String ln, Gender g, int nomr){
firstName = fn;
lastName = ln;
gender = g;
noOfModulesRegistered = nomr;
}

When another class is implemented like the example above, can the parameter names differ from the parametrize constructor in the Student class and the parametrize constructor of the PostGraduateStudent Class? Or must the parameter names be the same?

In the PostGraduateStudent what does the word super means? What is the purpose of the word?

Yes, the names may differ but not their sequence.
The word super is used to call the constructor of extended class, student in this case. It is the correct way of calling a constructor inside another constructor. You can see
super(fn,ln,g,nomr); as student(fn,ln,g,nomr);