Rilles are long, narrow depressions formed on the surface of the Moon. Scientists have identified various synonyms for Rilles, such as channels, grooves, valleys, and fissures. These terms describe different types of Rilles, depending on their shape and size. Channels and grooves are shallow depressions with U-shaped cross-sections, while valleys are deeper and wider with V-shaped cross-sections. Fissures are narrow and elongated cracks, often caused by volcanic activity. Rilles play a crucial role in the study of the Moon's geology, providing significant insights into the lunar surface's formation and evolution. By exploring and classifying these Rilles, scientists can uncover more about the Moon's geological history and understand more about its composition and characteristics.