Hi, I have problems with the words used in some exercises( my book refers to net book value, it does not mention book value)

1. Is net book value the same as book value?
2. What is the book value formula or the net book value formula? (My book shows; net book value= cost of asset minus ( - ) accumulated depreciation
3. When we have an information about paid dividends. When I do the journal entry I have to use retained earnings instead of dividends?Example:

Paid $1,000 in dividends, the journal entry should be retained earnings? or dividends? 1,000

cash 1,000

Thanks