I called them f-in, because they got really boring at that point. For me, every time high school curriculum touched on probability theory or statistics, it'd be urn o'clock. But then, come statistics at my university applied CS studies, there they were again. More advanced materials, but same mental model, as if it was something natural, or interesting, to people.

Also, calling them "urns". There are exactly two common usages of the word "urn" in Polish - the box you put your votes into during elections, and the vase for storing ashes of cremated people.