The Great Material Continuum, sometimes just called the "Great Continuum", was a spiritual concept from Ferengi culture.
Ferengi saw the universe as having "millions of worlds, all with too much of one, and not enough of the other", with the Great Continuum flowing through them all like a mighty river, from have to want and back again. As such, it was the force that bound the universe together. To get everything you desire in life, you had to have your ship navigate the Continuum with skill and grace. In practice, this meant that material taken from one area had to be replaced or paid for through another means, while avoiding obstacles and pitfalls. Rom noted that river could be very treacherous.
The Nagus in particular was responsible for standing "at the bow of the Ferengi ship of state", navigating the waters of the Great Material Continuum, avoiding the shoals of bankruptcy and seeking the strong winds of prosperity.