Nadion

Part of speech: noun

Definitions

1. A hypothetical subatomic particle proposed in theoretical physics as a possible component of dark matter or a partner to known particles
2. A speculative particle suggested by some physics theories, which would interact only weakly with ordinary matter
3. An unproven particle posited in certain physics models as an element of the unseen mass of the universe

Etymology: Nadion is a technical coinage, not an ancient word. It was formed in the early 1830s by Michael Faraday, who needed names for the two electrodes in the electrolysis experiments he was running at the time. Faraday had already proposed "anode" for the electrode where current entered an electrolyte, and "cathode" for the one where it left, and he wanted matching terms for the ions travelling toward each electrode. He took the Greek "nadion," the neuter form of "nadios," meaning "swimming" or "going down," and paired it with "kation" (going up) and "anion" (going up or going down) to describe the directions in which particles moved. The pairing was short-lived in its original sense. "Nadion" was used for a particle moving toward the anode, but the terms were soon revised as chemists refined their understanding of charge and particle movement. Today the word survives mainly in older chemistry texts and in discussions of the history of electrochemical terminology, where it marks a stage in how scientists first tried to name the particles they could only infer.