The red represents the blood of those who died in the country's struggle for independence from the Great Britain, the gold represents the mineral wealth of the country, the green symbolises the country's rich forests and natural wealth, and the black star is the symbol of African emancipation. The black star was adopted from the flag of the Black Star Line, a shipping line incorporated by Marcus Garvey that operated from 1919 to 1922. It is where the Ghana national football team draw their nickname, the Black Stars, from.

What does the star on the ghana flag mean? Let's have some stream of consciousness first.
The relevant sentence in the passage is: The red represents the blood of those who died in the country's struggle for independence from the Great Britain, the gold represents the mineral wealth of the country, the green symbolises the country's rich forests and natural wealth, and the black star is the symbol of African emancipation. So, the answer is the symbol of African emancipation.