Here is how the developer describes the game:
ABZU is a game that will take players on an epic adventure into the depths of the ocean, where they will encounter majestic creatures and discover long lost secrets. The game draws inspiration from a deep, innate story that we all carry in our collective subconscious, a universal origin myth that resonates across cultures. As such, the name ABZÛ references a concept from the oldest Mesopotamian mythology: it is the combination of two ancient words Ab, meaning ocean, and Zû, meaning to know. Essentially, ABZÛ is the ocean of wisdom.
Take a look at the new ABZU E3 PS4 trailer:
Source: Giant Squid