When talking about C++, what precisely does it imply to refer to something as a "pointer variable"? How is it used in the process?

So, in C++ I understand using pointers and references in as function arguments, but need a bit of in depth explanation as to understanding dynamic memory allocation, and how to know when they are allocated?   It is because I am confused on how memory works whenever I use pointers or references or allocating memory in C++?

In C++, what does the term "pointer variable" mean? What does it do?

How does C++'s data hiding function and what is it? What kinds of access specifiers are there?