The property of a living organism to emit light is called as:

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the term that describes the ability of living organisms to emit light.

2. **Identifying the Term**: The property of emitting light in living organisms is specifically known as "bioluminescence."

3. **Context of Bioluminescence**: This phenomenon is observed in various organisms, particularly in marine species. It is a characteristic feature of organisms belonging to the phylum Ctenophora, which are known for their ability to produce light.

4. **Mechanism of Light Emission**: The light emission occurs through specialized cells called "Photocytes." These cells contain photoproteins, which are proteins activated by calcium ions, enabling the organism to emit light.

5. **Examples of Organisms**: Bioluminescence can be found in both marine vertebrates and invertebrates, showcasing a wide range of species that exhibit this fascinating ability.

6. **Conclusion**: Therefore, the answer to the question is that the property of a living organism to emit light is called "bioluminescence."

---