extrusive

/eks'tru:siv/

Friendly

Word: Extrusive

Part of Speech: Adjective

Basic Definition: The word "extrusive" describes a type of rock material that is formed when molten (hot and liquid) rock comes out of the Earth through cracks in the surface and cools down quickly. This process often happens during volcanic eruptions.

Usage Instructions:

• Use "extrusive" when talking about geology or earth sciences, especially when discussing types of igneous rocks.
• It is often used in contrast to "intrusive," which refers to rocks that form from molten material that cools slowly beneath the Earth's surface.

Example Sentence:

• "Basalt is an extrusive rock that forms when lava cools quickly after erupting from a volcano."

Advanced Usage:

• In geology, you might hear phrases like "extrusive igneous rock," which refers specifically to igneous rocks that are formed from lava that has erupted onto the surface.

Word Variants:

• Extrusion (noun): The process of forcing molten rock out of the Earth.
• Extrusively (adverb): In a manner that relates to extrusive processes.

Different Meanings:

• While "extrusive" primarily refers to geology, in a broader sense, it can describe any process where something is forced out or expelled, although this usage is less common.

Synonyms:

• Volcanic (when referring to rocks formed by volcanic activity)
• Eruptive (related to eruptions)

Idioms and Phrasal Verbs:

• There are no specific idioms or phrasal verbs that use "extrusive," but you might encounter phrases like "extrusive activity," referring to volcanic activity where materials are expelled from the Earth.

Conclusion:

In summary, "extrusive" is a term used mainly in geology to describe rocks formed from lava that cools quickly after being expelled from the Earth's surface.

Academic

Adjective

1. of rock material; forced out while molten through cracks in the earth's surface