Abstract Base Classes (ABCs) in Python are a fundamental concept in object-oriented programming that facilitate the creation of consistent interfaces by defining a set of common methods and attributes that must be implemented by any subclass. Unlike regular classes, ABCs enforce implementation, ensuring that objects of different classes can be used interchangeably, and they provide runtime type-checking to catch errors. ABCs differ from interfaces in that they can include concrete methods, while interfaces only define method signatures. This structure promotes code reuse, modularity, and consistency, making it easier to extend and modify code, such as in plugin architectures where ABCs ensure compatibility and adherence to a common set of rules. ABCs are implemented using the `abc` module, with `ABCMeta` serving as the metaclass and `@abstractmethod` decorator indicating abstract methods. Real-world applications of ABCs include standardizing behaviors across various subclasses, ensuring compatibility in large projects, and creating plugin architectures. Overall, ABCs help enforce contracts, facilitate type-checking, and encourage modular and predictable code development.