“Promethean” comes from the name of the Greek demigod Prometheus. In Greek mythology, Prometheus was a demigod made from clay who stole fire from Mount Olympus to share with humankind. As an adjective, “Promethean” describes people or things that are rebelliously creative, calling back to the courageous acts of Prometheus in creating fire. It’s a useful term for branding and product purposes: In the early 1830s (before modern matches were invented), to make fire one might use a small glass vial containing sulphuric acid and a flammable mixture that would ignite when combined. These glass tubes were called “Prometheans.”