"Understanding and expressing scalable concurrency"
( https://people.mpi-sws.org/~turon/turon-thesis.pdf )
addresses the difference between parallelism and concurrency in detail (page 11-12). Rereading that, I'm pretty sure the title is wrong.
In French, the word 'concurrent' literally means 'competitor' - Which in our case implies competition for computational resources (E.g. specific memory locations) - On the other hand, the 'Thinking in Parallel' article talks about how to partition resources in a way which removes the element of competition between processes - So the word 'Parallel' seems fitting.
Concurrent is for separate entities working together in a coordinated manner. A prime example is threads working together on a work queue. Parallel is for a singular entity doing multiple things at the same time. For example a vector instruction that does multiple additions at the same time.