According to Genesis, Noah opened a window in the Ark before sending out the raven.
Genesis 8:6 says that after forty days Noah opened the window he had made in the ark. He then sent out the raven to test whether the waters had receded. The window is part of the ark's original construction instructions, which also mention an opening in the side.
Translations vary in how they render some architectural terms, especially the opening described in Genesis 6. The raven passage, however, explicitly refers to a window. The text does not provide a full design, explain its mechanism, or say that it was a glass window in the modern sense.
This detail is sometimes blended with the ark's door in retellings. Genesis separately says that God shut Noah in through the door before the Flood, while the window is used later to observe conditions and release birds. The two openings serve different narrative functions.