Was the article written by an llm difference engine? In that it failed at discussing the differences of the two and really just regurgitated the etymologies and ancient definitions of the two terms with no insight about modern usages. My quick difference as a matter of opinion only is that engine is related to carnot some heat cycle creates enables work that can be turned into locomotion. Motor is a superset, and is some system, process or machine that turns potential energy into kinetic energy. That is my opinion, of which i am open to, in fact very interested in reading others. Unfortunately this was not that article, instead you get a brief history lessons on words, with the thesis that some word's meanings change over time (allow me to pick my jaw off the floor) and don't worry about delineating the two terms because they pretty much mean the same thing. Not what i was expecting from mit engineering.