Multi-threaded refers to a programming technique that allows multiple threads to run concurrently within a single process. A thread is a smaller unit of a program that can be executed independently, enabling tasks to be performed simultaneously. This can improve the efficiency and performance of applications, especially on multi-core processors, where different threads can be executed on separate cores. In a multi-threaded environment, tasks such as data processing, user interface updates, and network communication can occur at the same time. This approach is commonly used in software development for applications like web servers and video games, where responsiveness and speed are crucial for user experience.