'Dark' in the Bible

They covered the surface of all the ground, so that the ground became dark with them, and they ate all the vegetation of the ground and all the fruit of the trees that the hail had left. Nothing green remained on the trees or on anything that grew in the fields throughout the whole land of Egypt.

It came between the Egyptian camp and the Israelite camp; it was a dark cloud and it lit up the night so that one camp did not come near the other the whole night.