Scope vs Visiblity vs Lifetime vs Accessibility vs etc

Scope, visibility and accessibility are all really talking about the same thing; given a particular declaration when can that declaration be referenced. Scope is the most general term and encompasses both visibility and accessibility and the referenced quote is adequate. Visibility and accessibility are usually applied to the members of a class as it is easier to think of them as being "hidden" or "not visible" as opposed to out of scope; that is, myMember is either private, protected or public controlling the visibility of the member in a class and its decedents. When inside a method of a class, all members are accessible or visible but only public members are from outside the class. protected members are only accessible or visible from the class itself or one of its derived classes. All of these contribute to the scope of myMember, that is the smallest region of text that can access myMember.

The parenthetical about lifetime is technically accurate for local variables but is really mixing a runtime concept, lifetime, with a compile-time or lexical concept, scope. You should ignore it. It is more confusing than helpful when trying to understand scope. Understanding lifetime is important to understand when a destructor is run and is related to scope but not important in understanding scope.

I believe those terms are the same for all the languages, since it's how the Compiler (or Interpreter) will save internally the variables, and access them.

[Edit] The C example is better for this purpose.

#include <stdio.h> int i = 4; void myMethod(void) { int j = 3; printf("I can see var i from the outside: %d\n", i); } void anotherMethod(void) { int i = 2; printf("Scope of 'i' declared outside of the method is valid, but it's not visible.\n"); printf("You'll see the 'i' variable declared inside the method: %d\n", i); } int main(void) { myMethod(); printf("Asking for j will give an error, because it's outside the scope\n"); anotherMethod(); }