SOLID stands for five basic principles of object-oriented programming and design. The acronym was first used by Robert C. Martin in his 2000 paper Design Principles and Design Patterns. The five principles are Single Responsibility Principle (SRP), Open/Closed Principle (OCP), Liskov Substitution Principle (LSP), Interface Segregation Principle (ISP), and Dependency Inversion Principle (DIP). These principles help software architects create better code that is easier to understand, maintain, and extend.   Single Responsibility Principle (SRP)   The Single Responsibility Principle states that every class should be responsible for one thing only, or in other words, it should have only one reason to change. This helps prevent code from becoming overly complicated or hard to read while also making it easier to debug any issues that may arise. By limiting the scope of a class, developers can create more modular code that can easily be reused in different contexts.   Open/Closed Principle (OCP)   The Open/Closed Principle states that classes should be open for extension but closed for modification. This allows developers to extend the functionality of their code without needing to make changes to existing classes or functions. It also helps ensure code stability since new features can be added without breaking existing ones.   Liskov Substitution Principle (LSP)   The Liskov Substitution principle states that any parent class should be able to be substituted with any child class without affecting the correctness of the program. This principle helps ensure that objects behave as expected when they are passed around between different parts of an application or library.   Interface Segregation Principle (ISP)   The Interface Segregation Principle states that interfaces should not be too generic but instead should provide specific interfaces tailored to each client’s needs. This allows developers to create interfaces that are focused on specific tasks while still providing enough flexibility so they can easily be adapted if needed in the future.   Dependency Inversion Principle (DIP)   The Dependency Inversion principle states that high-level modules should not depend on low-level modules but rather both should depend on abstractions instead. This helps ensure loose coupling between components which makes them easier to test, maintain, and reuse across multiple projects or applications.