Just one last thought, you can download some of the delves as a PDF from the RPGA site as long as you are a Herald level GM. I haven't looked lately, but I know at least one or two are up there. You can take a look at them and get a better understanding of what they are in the current form.
No, that's not it at all. Dungeon Delve (note capitals) is a book full of dungeon delves. Dungeon delves are like mini-dungeons. See Firelance's quote above.