I've never really heard anyone define OOP past "I'd know it when I see it". At least this article explicitly picks polymorphism as a language feature that defin

I've never really heard anyone define OOP past "I'd know it when I see it". At least this article explicitly picks polymorphism as a language feature that defines whether it is OO or not. But basically every modern language has polymorphism in some form - even C has function pointers. OOP is just another in a long line of broad categories that doesn't really mean much. Pretty much all languages are procedural, functional, object-oriented, declarative languages.