However, if it is used that easy, then yes, absolutely, it fits my definition.

Using the Executor class as a threadset might also make it fit my definition, but I think my opinion of my definition has changed in the two years since I wrote it. I may have to revisit it because I think it may be useful to only consider concurrency that has the same block structure as structured programming does, whereas my current definition allows for passing a threadset around as a first-class value.

tl;dr: yes, it probably fits, but that might mean my definition need changing, except in the case of try-with-resources.