In Genesis, the Hebrew term commonly transliterated as tzohar refers to the Ark’s roof opening or illuminating feature.
Genesis 6:16 instructs Noah to make a tzohar for the Ark and finish it to within a cubit of the top. English translations differ: some render the word as “window,” while others use “roof,” “opening,” or a term associated with light. Because the Hebrew word is rare and its precise meaning is uncertain, tzohar is safer than claiming that every translation describes exactly the same architectural feature.
The verse separately mentions a door in the Ark’s side and three decks. Those details show that the opening was part of a broader set of construction instructions rather than the only source of ventilation or light described in the passage.
Later Jewish interpretation and popular retellings sometimes explain the tzohar as a luminous stone, but that interpretation is not explicit in Genesis itself.