A fissure or narrow channel on the moon’s surface.
More example sentences
- He prefers looking in and near smallish craters and the rilles - long, sharp lines or faults.
- But we know that the Moon is not spherical: rather, it is mountainous in some regions, deep canyons and rills permeating the surface elsewhere, and it is pockmarked with craters, too.
Definition of rille in:
- The US English dictionary