Blizzard filed for a new trademark "Catacylsm" on Jun 26th according to the US Patent and TM office.
The filing can be found here.

Most likely this is for the next xpac that many anticipate being announced at this years Blizzcon.

From WoWWiki.com is an explanation of 'The Great Sundering' which is also called 'The Catacylsm'

The Great Sundering, also known as simply the Sundering or the Cataclysm,WRPG 185, 211 was a world event which reshaped Azeroth approximately 10,000 years ago at the end of the War of the Ancients. This event was triggered due to the Well of Eternity being destroyed.

Prior to the Sundering, there was only one continent on Azeroth, referred to as Kalimdor. In the catastrophic explosion, eighty percent of the land mass was destroyed,W3Man #? leaving behind the major continents and scattered islands that are known today: Northrend, Kezan, the Eastern Kingdoms, and the remnant still referred to as Kalimdor.

The site of the Well of Eternity became a swirling vortex of power known as the Maelstrom.

Stay tuned for further info as it develops!