Here is how I described the whole issue of PHP class aspect (property/method) accessing. Is it enough accurate?
Class aspects (properties/methods) can be accessed by the methods of other classes.
We could use an Access Modifier to limit such access:
* Public aspect - methods of all other classes can read/rewrite it.
* Protected aspect - methods of certain other classes can read/rewrite it.
* Private aspect - methods from other classes aren't allowed to read/rewrie it.