**Step-by-Step Solution:**
1. **Identify the Material**: The question asks about "Orlon". To answer this, we need to identify what Orlon is.
2. **Understand the Composition**: Orlon is a trade name. It is important to know that trade names are often used for specific types of materials or products. In this case, Orlon is a trade name for a synthetic fiber.
3. **Determine the Chemical Basis**: The chemical basis of Orlon is polyacrylonitrile. This means that Orlon is made from a polymer that is derived from the monomer acrylonitrile.
4. **Define Acrylonitrile**: Acrylonitrile is a chemical compound that is used to produce the polymer polyacrylonitrile. It is a colorless liquid that is important in the production of synthetic fibers.
5. **Conclude the Definition**: Therefore, Orlon can be defined as a synthetic fiber made from the polymer polyacrylonitrile, which is derived from the monomer acrylonitrile.
**Final Answer**: Orlon is a synthetic fiber made from polyacrylonitrile, which is derived from acrylonitrile.
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