Let’s take the Rhine Which goes from Switzerland to Netherlands. When and how did people start agreeing on giving-it the same name ? What about the alps going from southern France to Austria ? When did people agreed that it was the same mountain range ? And obviously what about the Gulf of Mexico ?
River Avon in the UK derives from Celtic word for river (Avon).
So its basically just River River
And as a result there are 8 or 9 rivers called “Avon” in the UK…
Major Major Major springs to mind.