In Genesis, what was Noah told to build into the Ark for light?

In Genesis, Noah was told to build a window into the Ark for light.

Genesis 6:16 describes the Ark’s design and includes a “window” or opening. The passage also mentions a door in the side and three levels or decks. English translations differ slightly in how they render the Hebrew term and the surrounding measurements, but the text clearly includes an opening associated with the Ark’s upper structure.

The window is not the same feature as the Ark’s door. Genesis says the door was in the side, while the window appears separately in the construction instructions. Later, Genesis records Noah opening the window after the Flood waters had receded enough for him to investigate conditions outside.