To make matters worse, airlines call this kind of trip "direct service".

I call it a "connection" or even a "one stop".

But the airlines continue to refer to this as a "direct flight".

I think that the term evolved from the olden days of railroad where a railcar stopped at other cities but ended up at the desired destination. Sometimes a train would split into 2 halves midway and some cars would continue on to different destinations, too. But the correct cars offerred "direct" service to xxx.