First of all - thanks to all on the forum for the clarifications provided over the last few days. You have eased my path significantly.
What I think I’ve realised is that the term trip as used in the Interrail context seems to be misleading. Trip as used in the app is a collection of potential moves from point A to point B, point B to point C, but also point B to points D, E, F, G & H - it’s like a pick list or a wish list. You can define any number of journeys in a trip, and you can travel on some or all of them. So it’s not actually a trip. Your actual trip may go A-B-C-H, or maybe A-B-C-E.
A trip in Interrail terms is only a list of possible travel legs which may or may not be taken.
A trip in ordinary usage is an actual journey - “I’m planning a trip from Edinburgh(A) to Nice(D), via London(B) and Paris(C).” or “I took a trip from Edinburgh(A) to Milan(H), via London(B) and Paris(C). I went to Milan instead of Nice because the weather was bad in Nice on the day.”
It may seem trivial, but from looking at the posts (even in the last 48 hours alone) asking about trips I think this issue causes a whole lot more confusion for travelers than it needs to.
What do others think? Is this something that the app should clarify to make everyones life easier? Does the app have language versions? What terminology do they use?