Earlier quoted context omitted.
You can't use the terms interchangeably. An "Executive producer" credit may be applied to lots of people who are not the showrunner. >This credit is given to the showrunner, or the head writer, and is sometimes also given to other important members of the production. These could include the show’s creator if different from the showrunner, other high-level writers (often future seasons’ showrunners), the owner/creator…
> You can't use the terms interchangeably Right, but what's the actual definition of the term "showrunner"? It's "the leading producer", according to the first sentence of that Wikipedia article. Why aren't we talking about the "lead[ing] producer"? Is the term "showrunner" perhaps just industry jargon that slipped out into the mainstream? EDIT: Go read through the Wikipedia:Talk page for 'Showrunner'[0], the quote "…
The showrunner can also have one of several actual official titles.
To answer the specific question in "Ack", it's a recognition of the person who is day-to-day the final decision maker. They can be overruled from above by executives (the showrunner is not the supreme content creator overlord), but the executives are overseeing a lineup or channel. The showrunner is the one who are making sure the season goes right as a full-time job.