Categorize the following words as fruits or vegetables: blueberries, onion, tomatoes, grapefruit.
- Fruits: blueberries, tomatoes, grapefruit
- Vegetables: onion
Complete the following task based on the instruction and optional input provided.### Instruction:
Categorize the following words as fruits or vegetables: blueberries, onion, tomatoes, grapefruit.

### Output:
- Fruits: blueberries, tomatoes, grapefruit
- Vegetables: onion