In C, you can only pass by pointer. It's etched into the language.
Also, if you're talking programming languages, it's better to use programming-language specific words over more general ones.
If I say, you should store a reference to that and that, it might imply, in C++, that you should actually store a reference, and not a pointer.
So long story short, it's pass by pointer or nothing in my book, though not necessarily anyone else's.