This just came up in a game I was playing. It may apply to other characters too, but the one in question is the chase Batman from AA up on the pillar. He has a special power that allows him to be Stealth on the rim of elevated terrain. We first looked up what the rim was as defined in the glossary. It said any square of elevated terrain with a red line on it but the actual entry in the rulebook adds on to it by saying that the square also has to be adjacent to a square of lower elevation. The difference only makes a difference on maps with multiple levels of elevation. They have red lines surrounding each layer of elevated terrain, which by the glossary definition, allows Batman to stealth so long as he is beside a red line pretty much. I assume the actual entry trumps the glossary, right? but then why are they different?

The glossary, in general, is a quick summation of concepts, not an accurate restatement of the terms as defined in more depth. There are a lot of glossary entries that are lacking in important details. In general, you shouldn't use the glossary as a definitive resource.