The Orpisay Nebula was a nebula located in the Delta Quadrant. It was also a star nursery.
In 2376 aboard the USS Voyager, Icheb was able to enhance the resolution of the long-range sensors to detect the Orpisay Nebula and a star forming in it, even though Voyager had previously moved out of range of the nebula. (VOY: "Child's Play")
In the Star Trek Encyclopedia (4th ed., vol. 2, p. 114), the nebula's name was spelled "Orpissay Nebula".