Dot notation is a way to access properties and methods of objects in programming languages like JavaScript and Python. It uses a dot (.) followed by the property or method name to retrieve or manipulate data. For example, if you have an object called car, you can access its color property using car.color. This notation is particularly useful for organizing and managing complex data structures. By using dot notation, developers can easily navigate through nested objects. For instance, if car has a property engine, you can access its type with car.engine.type. This makes code more readable and maintainable.