The term 'Lunar Surface Feature' refers to two features found on the surface of the moon: a CRATER and a rille. A CRATER is a large, bowl-shaped depression on the surface of a planet or moon, usually caused by an impact from a meteorite or other celestial body. A rille is a long, narrow, winding valley or trench on the surface of a planet or moon, typically formed by volcanic activity or tectonic movement.