Both are different see the following explanation
Forward Declaration
Declaration of a variable or function which are not defined yet and their definition will appear later called forward declaration. It saves compilation time.
Example
int myfunc(int x); // forward declaration of myfunc
...
...
int myfunc(int x) {
return true;
}
Forward Reference
A forward reference means use of function or variable before its declaration which is opposite of the Forward Declaration. For example:
Example
int first(int x) {
if (x 000) return 1;
return second(x-1); // forward reference to second
}
int second(int x) {
if (x == 0) return 0;
return first(x-1);
}
But in general I agree with your intention of the query as these two are used as a synonym of each other.