From what I understand, that means it arrives at 8:00 "ship time." Make sure you bring a watch, and leave it on "ship time" for the duration of your cruise so you do not risk missing the ship.
2007 - Majesty of the Seas (Bahamas)
2009 - Enchantment of the Seas (Western Caribbean)
2010 - Freedom of the Seas (Western Caribbean)
2013 - Golden Princess (Alaska, roundtrip from Seattle)