### Step-by-Step Solution:
1. **Definition of Livestock**: The term 'livestock' refers to domesticated animals that are raised primarily for agricultural purposes. These animals are kept for their utility in providing food, labor, and other products.
2. **Categories of Livestock**: Livestock can be categorized into different groups:
- **Domestic Animals**: These include animals like cattle, sheep, goats, and pigs that are raised for food, fiber, or labor.
- **Poultry Animals**: This category includes birds such as chickens, ducks, turkeys, and geese that are raised for their eggs and meat.
3. **Exclusion of Pet Animals**: While pets like cats and dogs are domesticated, they do not fall under the category of livestock because they are not raised for agricultural purposes or profit.
4. **Economic Importance**: Livestock plays a crucial role in agriculture and economy, providing products such as meat, milk, eggs, wool, and leather, which are essential for human consumption and various industries.
5. **Conclusion**: Therefore, the term 'livestock' encompasses both domestic animals and poultry animals, but it does not include pet animals. The correct answer is that livestock refers to domestic and poultry animals.
### Final Answer:
The term 'livestock' means domestic animals and poultry animals, but not pet animals.
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