volcanicrock
nounUK /vɒlˈkænɪk rɒk/
US /vɑːlˈkænɪk rɑːk/
Volcanic rock is rock that comes from a volcano.
The beach was covered in black volcanic rock.
OTHER MEANINGS
2. Rock formed when hot lava cools and hardens.
Scientists studied the volcanic rock to learn about the eruption.
3. A dark, rough stone often used in gardens.
They put volcanic rock around the plants to help them grow.
4. A type of rock that can float on water when full of air holes.
He dropped a piece of volcanic rock in the water and it floated.