According to Genesis, Noah’s Ark had a door in its side.
Genesis 6:16 gives construction instructions for the Ark and says that Noah should make a door in its side. The same verse describes three decks and an opening or window, making the door one of several specific structural features named in the account.
Later, Genesis 7:16 says that Noah and the animals entered the Ark, and that the Lord shut the door behind them. The wording emphasizes the closing of the vessel before the Flood waters rose. Genesis does not describe a separate ramp, staircase, or gatehouse.
The door is sometimes merged in retellings with the Ark’s window. They are distinct features in the text: the door is placed in the side, while the opening is mentioned separately in the construction instructions.