Computer systems where components run across multiple networked machines but appear as a single coherent system. The backbone of modern cloud architecture — handling challenges like network partitions, consistency, and fault tolerance. The CAP theorem states that distributed systems can only guarantee two of: Consistency, Availability, and Partition tolerance.
A global e-commerce platform distributes its inventory database across multiple cloud regions. The distributed system ensures that when a user in Tokyo buys an item, inventory is updated consistently across servers in North America and Europe within milliseconds.