https://en.wikipedia.org/wiki/Wankel_engine https://en.wikipedia.org/wiki/Wankel_engine https://www.britannica.com/technology/Wankel-engine https://www.britann

https://en.wikipedia.org/wiki/Wankel_engine https://en.wikipedia.org/wiki/Wankel_engine https://www.britannica.com/technology/Wankel-engine https://www.britannica.com/technology/Wankel-engine both seem to disagree with your technical definition. at the very least, the colloquial usage is broad enough that adhering to some archaic technical definition isn't sufficient to explain some confusion. even this wiki article says it's obsolete https://en.wikipedia.org/wiki/Rotary_engine https://en.wikipedia.org/wiki/Rotary_engine