What elements are usually excluded from the definition of object-oriented programming?

Elements that are usually not included in the definition of object-oriented programming (OOP) are:

• Procedural programming — OOP focuses on objects and their interactions, not on a sequence of procedures.
• Global variables — OOP aims to encapsulate data within objects.
• Multiple inheritance (in some languages) — is not always a mandatory part of OOP.
• Functional programming — is a separate paradigm.

The main elements of OOP are classes, objects, inheritance, encapsulation, and polymorphism.