The asterisk *  is a "wildcard" option. It means that it can be filled by any number in its place.

writing 5* - means that it covers everything with 55 in front:

• 55
• 550
• 551
• 552
• 553
• 554
• 555
• 556
• 557
• 558
• 559

Okay, so why might I need this?

The asterisk is useful if you need to place a block on a set of pages, but it may have various endings. The opposite might also be true - maybe you want to have a block display on all pages, except a set of pages with a similar beginning.

On the edit page of the block, scroll to the visibility settings near the bottom of the page.

Choose your option: 

• all pages except those listed
• only the listed pages

(ignore the last option)

The most common instance to use this option is for the checkout pages in your store.
If you have a block you only want to have appear on checkout pages, type the following into the box:
 

checkout/*

This will cover all checkout pages.