Aspect of the Moon determined by past volcanic activity, meteorite impact and soil fractures.
Steep rock face shaped by a sea.
Small plain of hardened lava located along the edges of a sea.
A very large sea.
Circular basin dug out by the impact of a meteorite.
Mountain usually surrounding a cirque.
Vestiges of the walls of a once-large crater; semicircular in shape, it can span hundreds of miles.
Designates the vast plains of hardened lava forming the dark regions; younger than the highlands, these cover 15% of the surface.
Small isolated plain of hardened lava.
Designates bright regions riddled with craters; these oldest regions cover 85% of the surface.
Band that radiates from a young crater, the result of matter ejected during a meteorite impact.
Vast crater characterized by remarkable relief; varies between 12 and 120 mi in diameter.