In the Genesis Flood story, pitch sealed Noah’s Ark against water.
Genesis 6:14 tells Noah to cover the Ark inside and outside with pitch. The Hebrew term is related to bitumen or a waterproofing substance, and English translations commonly render it as “pitch.” This coating was separate from the wood used to construct the vessel.
Pitch was a practical ancient sealant. Bituminous materials occur naturally in parts of the Near East and were used historically to make boats and other structures more resistant to water. The Genesis wording therefore combines a wooden vessel with an exterior and interior waterproof coating.
The passage does not identify the precise chemical composition or source of the pitch. It also does not describe a modern-style paint system. A common mix-up is to answer “gopher wood,” which names the Ark’s construction material rather than the substance used to seal it.