• These patterns are concerned with object relationships and the structure of classes or objects. They help to add new functionality without having to modify the entire system. They ensure that if one part of a system changes, the whole system does not change with it.

  • In plain words

  • Structural patterns are mostly concerned with object composition or in other words how the entities can use each other. Or yet another explanation would be, they help in answering “How to build a software component?”

  • Wikipedia says

In software engineering, structural design patterns are design patterns that ease the design by identifying a simple way to realize relationships between entities.