Genesis says Noah made a window in the Ark’s roof.
Genesis 6:16 includes an instruction concerning a window or opening associated with the Ark’s roof. The passage also mentions a door at the side and the vessel’s three decks. After the Flood began to recede, Genesis 8:6 says Noah opened the window he had made.
Translations differ in how they render some details of the Hebrew wording, including the exact shape and placement of the opening. “Window” is the traditional English term and is the standard answer to this question, while some discussions describe it more generally as an opening for light or ventilation.
The window is important to the narrative because Noah uses it when sending out the raven and the dove. It should not be confused with the Ark’s side door, which Genesis identifies separately. Later artistic reconstructions often add multiple openings, but Genesis specifically mentions this window.