What is the difference between aggregation and compositional association in object-oriented programming?

Aggregation and composition are two types of relationships between objects in OOP, reflecting ownership and the lifecycle of objects.

• Aggregation is a weak relationship where the 'owner' object contains a reference to another object but is not responsible for its lifecycle. The part object can exist independently of the whole. For example, a 'Car' class can aggregate 'Passenger' objects, but passengers can exist separately.

• Composition is a strong relationship where the whole fully owns the part object, and the lifecycle of the part depends on the whole. If the whole is destroyed, the parts are also destroyed. For example, a 'House' class composes 'Room' objects: rooms do not exist without a house.

In Python, this is usually expressed through object ownership and references, but the conceptual difference remains.