DDD stands for Domain-Driven Design, which is an approach to software development that focuses on modeling complex business domains and aligning the software design with the domain. It was introduced by Eric Evans in his book “Domain-Driven Design: Tackling Complexity in the Heart of Software.”

Inversion of Control (IoC) is a design principle in software development where the control flow of a system is inverted or shifted from the application code to an external framework or container. In a traditional or imperative programming model, the main application code typically controls the flow of execution and manages the creation and lifetimes of objects. In contrast, with Inversion of Control, this control is handed over to an external entity, often referred to as an IoC container.

The SOLID principles are a set of design principles that aim to guide software developers in writing code that is maintainable, flexible, and easy to understand. These principles were introduced by Robert C. Martin (also known as Uncle Bob) and have become widely accepted as best practices in object-oriented programming.