What is the Facade pattern? How does it differ from Adapter?

Facade provides a single, simplified interface in front of a complex subsystem with many interacting classes, hiding that complexity from the client — e.g. a single `OrderFacade.placeOrder()` method that internally coordinates inventory, payment, and shipping services. Adapter also wraps something, but its purpose is different: Adapter converts one incompatible interface into another the client already expects, while Facade simplifies an interface the client would otherwise have to navigate directly.