A quadrant refers to one quarter of the galaxy. The four quadrants are the Alhpa, Beta, Gamma, and Delta Quadrants. Star Trek: Enterprise, The Original Series, and The Next Generation, take place primarily in the Alpha and Beta Quadrants. In Star Trek: Deep Space Nine, Captain Sisko, and Lietenant Dax find a wormhole to the Gamma Quadrant, where it is later learned that the Dominion control. In Star Trek: Voyager, the starship, Voyager, is pulled to the Delta Quadrant by an alien, and spends the rest of the series attempting to return to the Alpha Quadrant. However in the Original Series, the term is used inconsistently.