Formation of coal from matter under the earth at high temperature and pressure in the absence of oxygen over millions of years.

Answer

**Step-by-Step Solution:**

1. **Understanding the Statement**: The statement describes a process involving the transformation of organic matter into coal. It highlights specific conditions: high temperature, high pressure, absence of oxygen, and a long duration (millions of years).

2. **Identifying the Process**: The key elements of the statement point towards a geological process. The transformation of organic material into coal under these conditions is a well-known process in geology and chemistry.

3. **Defining the Process**: The process that describes the formation of coal from organic matter, subjected to high temperature and pressure, and occurring over millions of years in the absence of oxygen is known as **carbonization**.

4. **Conclusion**: Therefore, the name of the process that describes the formation of coal under these specific conditions is **carbonization**.

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