In OOP languages, members of a class have a specific scope that indicates visibility. Standard visibility includes private, protected, and public. Private members are usable by the defining class only (fully encapsulated). They are invisible outside of the class except by friendly classes.
Protected members are usable by the defining class and descendant classes only (plus friendly classes). Public members are usable wherever its class can be referenced.
Languages Focus: Member Visibility
Traditional member visibility specifiers for fully OOP languages are private, protected, and public. Many modern OOP languages implement additional member visibilities.
Additional member modifiers are documented under the Member Modifiers topic.
VB Classic Member Visibility
In VB Classic, the keywords Private, Friend, Public, and Static are used to set access levels for declared elements.