[Turtle91]

I imagine the way to differentiate is to ask yourself what it would sound like if you were listening to an assistive technology reading the passage aloud. Some of them will actually say the word "Quote" aloud before they start reading anything in a blockquote to give the listener context.

If you don't mind a listener hearing "Quote" before any indented sentence, letter, banner, etc. then you could use a blockquote; otherwise a div would be more appropriate. Especially since you can make a div look exactly how you want - not just relying on a blockquote's visual default.

I also bow to Kevin's greater familiarity with section tags/aria labeling in ePub3!