Conoscope

Part of speech: noun

Definitions

1. An optical instrument that combines a polarizing microscope with a converging lens so that the interference figures of a crystal can be observed along its optic axis
2. A device used by mineralogists and physicists to view the interference patterns produced when polarized light passes through a crystal, revealing its optical axis
3. A polarized-light apparatus that lets the interference figure of a crystalline specimen be examined in convergent light to determine its optical character

Etymology: A conoscope is a compound built from two Greek-derived parts: "cono-", from Greek "kōnos", meaning cone, and "-scope", from Greek "skopein", meaning to look at or examine. The name describes what the instrument does. A polarizing microscope is combined with a converging lens so that the faint patterns, called interference figures, formed when polarized light passes through a crystal along its optic axis can be seen. Because the light converges in a cone-shaped beam through the specimen, the view resembles the cone of light the instrument generates, which is why the first element refers to it. The word's history is simple and transparent: a technical coinage assembled from classical roots to name a specialized laboratory tool, rather than a term that evolved through everyday speech. Its meaning has stayed fixed to the instrument itself, so the components of the name remain the clearest guide to what it is.