1. relating to or formed by volcanic rock that has cooled and solidified on the Earth’s surface
Usage: geology
2. tending to push outward or protrude

Examples

• Basalt is a common extrusive igneous rock formed from lava flows.
• The geologist identified several extrusive rock formations along the coastline.
• Obsidian is an extrusive volcanic glass that cools rapidly.
• The mountain’s extrusive layers tell the story of ancient eruptions.
• Extrusive rocks have smaller crystals than intrusive rocks due to rapid cooling.
• The extrusive nature of the cliff face made climbing difficult.
• Scientists studied the extrusive volcanic deposits in the region.