'Dense' in the Bible

The LORD did this, and dense swarms of insects came into the house of Pharaoh and into the houses of his servants. The land was ruined throughout Egypt because of the swarms of insects.

The Lord said to Moses, “I am going to come to you in a dense cloud, so that the people will hear when I speak with you and will always believe you.” Then Moses reported the people’s words to the Lord.

On the third day in the morning there was thunder and lightning and a dense cloud on the mountain, and the sound of a very loud horn; all the people who were in the camp trembled.