A pointer is a reference that helps a program find a piece of information. In some programming languages, it holds a location; in JavaScript, an object value can refer to shared data without exposing a memory address.
Imagine two labels pointing to the same settings box. If you change what is inside the box, both labels still lead to that changed information.
This matters when code shares objects: changing the object through one reference may affect what another part of the program sees. The exact details depend on the language.