>>Neither is (air)plane or (passenger) train, yet we're instructed to deplane and detrain.
>
>Of course, "train" is a verb, just having no relationship that I can see to the noun. Wait, now I see it. When you "train" something, you teach it to follow a particular path, kind of like the one the train has to follow.

Unless it's the sights that you train... when you don't really teach the panorama to go anywhere, but aim the rifle.