What does Joshua 10:12 mean?

On the day the Lord handed the Amorites over to Israel, Joshua spoke to the Lord while all Israel was watching. He said, 'Sun, stand still over Gibeon! Moon, stay put over the valley of Aijalon!' Joshua 10:12 - Modern Text Bible

(Joshua prays for more daylight so Israel can finish the battle, asking God to stop the sun and moon in their tracks.)