* Highlands: These are the older, mountainous regions of the Moon, composed primarily of anorthosite, a light-colored, feldspar-rich rock. They are heavily cratered and reflect more sunlight, making them appear brighter.

* Lunar maria: These are vast, dark plains that were formed by ancient volcanic eruptions. They are composed of basalt, a dark, volcanic rock, and appear darker than the highlands.

So, while both are light areas, they are distinguished by their composition and origin.