napṭu

Along the banks of the Euphrates, particularly near Hit in what is now central Iraq, natural petroleum seeps from the ground as a black, viscous liquid that also generates lighter, more volatile fractions — the substance the ancient Mesopotamians called napṭu or naphtu in Akkadian. Cuneiform texts from the third millennium BCE record napṭu as a commodity of practical importance: it was used to waterproof boats, baskets, and storage containers; as a mortar in brick construction; in lamps as a fuel; and in warfare, where burning napṭu thrown on enemies — a precursor to Greek fire — appears in military records. The Tower of Babel description in Genesis (chapters 10–11) refers to 'slime' (Hebrew ḥēmār) used as mortar — almost certainly the bituminous petroleum familiar to Mesopotamian builders. Napṭu was Mesopotamia's industrial fluid.

The word is etymologically connected to Akkadian *napāḥu*, 'to light, to kindle, to blow' — napṭu is the 'kindling fluid,' the liquid that ignites. This etymology was already embedded in the Akkadian name long before the Greeks encountered the substance. When Alexander the Great's armies crossed Mesopotamia in 331 BCE, they encountered the petroleum seeps and were astonished: court historian Chares of Mytilene records a demonstration in which a trail of naptha was set alight and burned along the ground. Greek writers recorded the substance as naphtha (νάφθα), borrowing the Akkadian name essentially intact. Strabo's Geography and Plutarch's Life of Alexander both mention naphtha in the Babylonian context, making it one of the earliest petroleum-related words in Greek literature.

From Greek, naphtha passed into Latin and subsequently into the European scientific vocabulary during the Renaissance, when alchemists and early chemists were classifying flammable substances. By the 17th century, naphtha was used in European chemistry to describe the lighter, more volatile fractions of petroleum and coal tar. The development of the petroleum industry in the 19th century — with commercial oil drilling beginning in Pennsylvania in 1859 and in Baku (Azerbaijan) in the 1870s — gave naphtha new industrial relevance. In petroleum refining, naphtha designates the light hydrocarbon fraction distilled from crude oil, boiling between approximately 30 and 200 degrees Celsius, used as a solvent, a fuel, and a feedstock for producing plastics and chemicals.

Today, naphtha is a fundamental term in petroleum chemistry and refining. Cracker plants that convert naphtha into ethylene — the building block of polyethylene plastic — process hundreds of millions of tonnes annually. The word in use in a Houston refinery or a Rotterdam petrochemical plant is, with minor phonetic adjustment, the same word Akkadian scribes used for the seeping petroleum of the Euphrates banks. Almost no one in the petroleum industry knows this. The Mesopotamian origin of naphtha is one of the more remarkable etymological continuities in modern industrial vocabulary: a civilization that used petroleum to waterproof boats named the substance, and we have not found a better name in four thousand years.