No, the river is the Rhine. Traiectum is the noun for transire (verb), going through. It was a place where you could cross the river, hence a strategic place to

No, the river is the Rhine. Traiectum is the noun for transire (verb), going through. It was a place where you could cross the river, hence a strategic place to build a castellum, as the Rhine was used as a natural border (limes) for the Roman Empire. The u stands for uut (old Dutch), meaning downstream. Although I am not 100% sure if U doesn't simply stand for uit, which means 'from'.