An oasis (/ou'eisis/; plural: oases /ou'eisi:z/) is an isolated area in a desert, typically surrounding a water source, such as a pound or a small lake. Oases also provide habitat for animals and even humans.

The lunar Oases are made fertile when sources of freshwater, from frozen aquifers, irrigate the surface via man-made wells after melting and purifying it in the reactor in the core.