'Tent door' in the Bible

And the LORD appeared to him in the plains 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 to thee according to the time of life; and lo, Sarah thy 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 to the tabernacle, that all the people rose, and stood every man at his tent-door, and looked after Moses, until he had gone into the tabernacle.

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