What is the difference between concurrency and parallelism?

Question

What is the difference between concurrency and parallelism?

Examples are appreciated.

Answer 1

Imagine learning a new programming language by watching a video tutorial. You need to pause the video, apply what been said in code then continue watching. That's concurrency.

Now you're a professional programmer. And you enjoy listening to calm music while coding. That's Parallelism.

As Andrew Gerrand said in GoLang Blog

Concurrency is about dealing with lots of things at once. Parallelism is about doing lots of things at once.

Enjoy.