User blog comment:Lost Labyrinth/The Sims Medieval: Pirates and Nobles has been announced by EA!/@comment-2225748-20110709142540/@comment-26744861-20110709143058

Technically, it's still an expansion yet it is being marketed as an Adventure Pack. Seeing as it's the first time EA have used something like this, I think it's probably safe to use the "Expansion pack" term for now.