Electroscope

Part of speech: noun

Definitions

1. An instrument designed to identify the presence of electrical charge by observing the movement of conductive elements
2. A device that indicates electric charge levels through the divergence of metallic leaves or filaments
3. A tool used to detect the presence of electric charge by showing movement of thin metallic parts when charged

Etymology: The instrument is named for the material it was built to study. Ancient Greeks called amber "ḗlektron", and in Latin it became "ēlectrum". Because rubbing amber makes it attract light objects, the Latin word gave English the prefix "electro-", which came to mean electricity itself. The ending comes from Greek "skopós", an observer or watcher, which shows up in "telescope" and "microscope". So the whole name means something like "electricity-watcher." The "-scope" element has a more ordinary origin than its famous relatives suggest. It derives from "skopein", "to look at", and it became a productive combining form in English, so "electroscope" was built from parts that were already well established. The word belongs to the same family of coinages as "microscope" and "telescope", which were likewise assembled from classical roots to name new instruments.