What is encapsulation in object-oriented programming?

Encapsulation is a fundamental principle of object-oriented programming that involves bundling the data (attributes) and methods (functions or procedures) that operate on the data into a single unit called a class. This organizational method allows developers to group related information and behavior, and it helps manage complexity by restricting access to the internal representation of the object.

By encapsulating attributes and methods, encapsulation promotes data hiding, which means that the internal state of an object can be shielded from direct access by the outside world. This protection allows only controlled interactions with the object's data, typically through public methods (often referred to as getters and setters) that safely manage how the data is accessed and modified. Such a structure enhances modularity, maintainability, and code reusability within programs.

For instance, consider a class named "Car" that has properties like "speed" and "fuelLevel" and methods like "accelerate()" and "refuel()". Users of the Car class can invoke these methods without needing to understand the intricate details of how the speed and fuel level are managed internally.

Thus, defining encapsulation as the bundling of data and methods within a single unit correctly captures the essence of this concept in object-oriented programming.