A process is an independent program that is currently being executed by the computer. It has its own memory space CPU time, and other resources (such as files or network connections). Processes are isolated from one another to ensure stability and security; a problem in one process generally does not affect another.
A thread, on the other hand, is the smallest unit of execution within a process. Multiple threads can exist inside a single process, each performing a different task. All threads in the same process share the same memory and resources, but operate independently.
Example:
Consider a web browser:
The entire browser application is one process. Within this process, different threads are responsible for: One thread is loading and rendering a webpage. The second thread is playing audio or video content. Another thread is downloading files in the background.
By using the above multiple threads, the browser can continue loading new content while playing a video, without making the user wait for one task to finish before starting another.