Actually, a "direct" flight can still have a change of aircraft (often involving a change of gauge), as long as all segments use the same flight number.

I understand the concept of direct/indirect/non-stop, but my original question is if there is actually any special terminology given to a flight that goes A-B-C(-D)?

Got it, thanks!

I flew the maiden IST-BOG-PTY last year to BOG, and the PTY passengers just stayed on board. Of course, I guess that will vary depending on the countries served, and from what I understand, TK has no cabotage rights between BOG-PTY and COO-ABJ.

Well...guess I'll see what happens eventually one day, maybe...thanks all!

I avoid direct flights like the plague, but I have seen flights where passengers are permitted to temporarily disembark at the intermediate stop. (In the old days, I recall getting a generic pass -- not directly tied to a specific passenger but handed to all thru-passengers who chose to disembark. If you did that and didn't reboard, you could potentially cause a delay for the plane as they try to reconcile their passenger numbers and locate the missing passenger in the airport.

Also, be aware of this when it involves international flights. In the case of countries that require airlines to submit passenger manifests, you could be in for some interesting conversations at Immigration if you arrive and the country isn't expecting you.

Yeah, that could be an interesting one actually...and I can imagine it would be particularly problematic in areas where bribes are fairly commonplace...!