A title from the Star Wars universe. When the New Order came to power, they used the existing administrative structure as a basis, keeping the galaxy divided into its physical and political sectors. The Rebellion used this to its advantage, knowing that lazy bureaucrats would not spare the effort to chase traitors between sectors.
Admiral Tarkin came up with a solution to this problem; he split the galaxy up into sectors based instead on the amount of rebellious activity. A single official - a Grand Moff - would oversee each region.
Emperor Palpatine liked this idea, and appointed Admiral Tarkin Grand Moff of the Outer Rim Territories.