'Tent door' in the Bible

And the LORD appeared unto him by the oaks of Mamre: and he sat in the tent door in the heat of the day;

And he lifted up his eyes and looked, and, lo, three men stood by him: and when he saw them, he ran to meet them from the tent door, and bowed himself toward the ground,

And he said, I will certainly return unto you according to the time of life; and, lo, Sarah your wife shall have a son. And Sarah heard it in the tent door, which was behind him.

And it came to pass, when Moses went out unto the tabernacle, that all the people rose up, and stood every man at his tent door, and looked after Moses, until he was gone into the tabernacle.

And all the people saw the pillar of cloud stand at the tabernacle door: and all the people rose up and worshiped, every man in his tent door.