system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What does the concept of entropy mean?
gpt
You can set off a stick of dynamite.  But you can't put it back together again.  The amount of disorder in the universe always increases.

Well, technically you could take all of the gasses etc produced in the explosion, refine them, process them, and after a lot of work end up with a stick of dynamite again.  But by introducing a lot of order to that random swirl of gasses, you will introduce even more disorder in the rest of the universe - e.g. you're burning stuff to generate electricity to power the machines, you likely have used pure chemicals as part of your reactions and now you have a load of mixed chemical waste, etc.  The amount of disorder in the universe always increases.

The "disorder" in this example is technically called "entropy".