1. a dark, fine-grained volcanic rock formed from cooled lava
Usage: geology

Examples

• The ancient lava flow created thick layers of basalt.
• Basalt columns formed as the molten rock cooled and contracted.
• The island’s cliffs are made of dark basalt rock.
• Geologists studied the basalt samples from the ocean floor.
• The road was paved with crushed basalt aggregate.
• Basalt is one of the most common types of volcanic rock on Earth.