I know we covered this at the beginning of our unit, but it bears repeating: the Host is a term for a wafer that is supposed to represent (or in some faiths, actually be) the flesh of Christ. It is supposed to have great spiritual power.
We also see a quick reference to Medusa in this chapter. I’m betting that most students are already familiar with Medusa, but just as a refresher, she was an Ancient Greek monster who had snakes (always with the snakes in this book!) for hair, and if you looked her in the eyes, she could turn you to stone. If you’re interested in more about what Medusa has meant to different people over the course of history, I would recommend this thoughtful article.