The word scroll has two main meanings:

1. A roll of paper or similar material with writing on it. Before books existed, people wrote on long sheets of papyrus or parchment and rolled them up like posters to store them. Ancient libraries were filled with scrolls instead of books. The Dead Sea Scrolls, discovered in caves in 1947, are famous ancient religious texts that survived for over 2,000 years, rolled up in clay jars. In fantasy stories and games, wizards often carry magical scrolls with spells written on them.
2. To move text or images up and down (or sideways) on a screen. When you scroll through a website or document, you're sliding the content to see what's above or below the visible part of the screen. You might scroll down to read more of an article or scroll up to review something you read earlier.

The connection between these meanings is clever. Both involve gradually revealing information that was previously out of view, whether by unrolling paper or sliding digital content.