In the biblical account of Noah’s Ark, pitch was placed on the vessel’s inside and outside. Genesis 6:14 instructs Noah to cover the ark with pitch, using the same general term for its interior and exterior surfaces.
Pitch is a waterproofing substance associated with bitumen or tar. In the story, its practical purpose is to seal the wooden vessel against water. The passage does not specify the exact source, recipe, or manufacturing process of the material.
The ark’s construction instructions also mention rooms and a door in its side. These features accompany the waterproofing instruction and present the vessel as a large enclosed structure prepared for a catastrophic flood.
Some translations use different words for the substance, such as tar or bitumen, because the underlying ancient terminology can be rendered in more than one way. “Pitch” is the traditional English answer and is distinct from oil, wax, or clay.