1. Plural of anorthosite; igneous rocks composed primarily of plagioclase feldspar, typically found in the Moon's highlands and in some terrestrial geological formations.
Usage: geology; technical

Examples

• Lunar anorthosites were collected during the Apollo missions and provided crucial evidence about the Moon's early geological history.
• The anorthosites found in the Adirondack Mountains are among the oldest rocks in North America.
• Scientists study anorthosites to understand the formation and differentiation of planetary bodies.
• The bright highlands of the Moon are largely composed of anorthosites.
• Anorthosites are characterized by their high aluminum content and light coloration.