I think that, while most people can't really articulate this well enough, there is a pretty good common understanding of what style of programming is OO: it's a

I think that, while most people can't really articulate this well enough, there is a pretty good common understanding of what style of programming is OO: it's a style of programming where code is quite deeply tied to data, especially modifications of persistent state (encapsulation), and where subtyping is commonly used to model program behavior (interfaces, inheritance, virtual dispatch, polymorphism). This would mostly contrast with procedural code, where code and data are much more separate - procedures often manipulate and pass around complex data structures -, and subtyping is not commonly used for program behavior; instead, flow control is usually explicit (e.g. switch()'ing on an enum value). It is also commonly contrasted to Functional Programming, where data is also loosely tied to code, with functions often reading (but usually not modifying) deep parts of complex data structures; and where higher order functions and sum types are used to achieve dynamic dispatch.