Roman d20

So what's Latin for Dungeons & Dragons? I thought 20-sided dice were a rather recent innovation but, no, here's one from 1800 years ago. The lot notes at Christie's say

Several polyhedra in various materials with similar symbols are known from the Roman period. Modern scholarship has not yet established the game for which these dice were used.

I have to wonder if they were used for games, for fortune-telling, or both?