Rille is a term that refers to a narrow channel or groove found on the surface of celestial bodies, particularly on the Moon. These features are often formed by volcanic activity or the movement of lava, creating long, winding depressions. Rilles can vary in size and shape, contributing to the diverse landscape of the lunar surface. In addition to the Moon, rilles can also be found on other planets and moons, such as Mars and Io, one of Jupiter's moons. Studying rilles helps scientists understand the geological history and processes of these celestial bodies, providing insights into their formation and evolution.