Engine shares a root with ingenious, and the first fire engines were just pumps
The word engine comes through Old French from Latin ingenium, the same source as ingenious. Before factories, it meant clever war machinery: catapults, trebuchets and battering rams were siege engines whose construction was guarded as a military secret. A cotton gin is simply an engine with its first syllable clipped off.
Meanings drifted during the Industrial Revolution, when nearly every new mechanical device got called an engine. Thomas Savery's early steam engines were really pumps, and the original fire engine was a water pump that horses hauled to the blaze. When internal combustion arrived, people used motor, from Latin for that which moves something, to separate it from the steam engines already pulling trains. Everyday English now treats the words as interchangeable, although some engineers reserve engine for machines that burn fuel and motor for those run by electricity, air or hydraulics. Rocketry ignores the rule and says rocket motor anyway.
Powered machines are ancient. Greek cranes and ship gear and Roman mine pumps relied on capstans, windlasses, treadmills and pulleys, and writers such as Vitruvius, Frontinus and Pliny the Elder treated them as ordinary. Strabo reports a water mill at Kaberia in the kingdom of Mithridates in the 1st century BC, and water wheels then spread across the Roman Empire. Ausonius wrote in the 4th century AD of a water-driven saw for cutting stone. Hero of Alexandria is credited with wind and steam devices including the aeolipile and a vending machine, often used for temple tricks like doors that opened by themselves.
Medieval engineers pushed further. In 1206 al-Jazari used a crank and connecting rod in two water-raising machines, and crude steam turbines were described by Taqi al-Din in 1551 and Giovanni Branca in 1629. China produced the gunpowder rocket in the 13th century, the simplest internal combustion engine, which could not sustain power but could hurl weapons and fireworks.
The modern era turned on efficiency. James Watt, improving on the 1712 Newcomen design between 1763 and 1775, sharply cut fuel use and, with Matthew Boulton, let factories rise far from rivers. Etienne Lenoir built the first commercially successful internal combustion engine in 1860, and the 1877 Otto cycle beat steam on power for its weight. In 1897 Karl Benz patented the flat, opposed-piston boxer layout later used in the Volkswagen Beetle and small propeller planes.
Source: Engine
