Threading vs Parallelism, how do they differ?

Daniel Moth (a former coworker of mine)- Threading/Concurrency vs Parallelism article explains it all.

Quoted:

To take advantage of multiple cores from our software, ultimately
threads have to be used. Because of this fact, some developers fall in
the trap of equating multithreading to parallelism. That is not
accurate…You can have multithreading on a single core machine, but
you can only have parallelism on a multi core machine

The quick test: If on a single core machine you are using threads and it makes perfect sense for your scenario, then you are not “doing parallelism”, you are just doing multithreading.