Pheochrome

Part of speech: noun, adjective

Definitions

1. A type of cell, found chiefly in the adrenal medulla, that turns brown when treated with chromium salts
2. A cell in the adrenal glands or nearby tissue that darkens to a brownish colour when exposed to chromium compounds
3. A chromaffin-type cell that takes on a brown stain after being treated with salts of chromium in laboratory staining

Etymology: "Pheochrome" is built from two parts: "pheo-", from Greek "phaios", meaning dusky or dark grey, and "-chrome", from Greek "chroma", meaning colour. Together they describe something with a dusky or dark colouring. The term is used in biology and medicine for cells, particularly those that stain darkly with certain chemical dyes. Its usage is specialised, so it is mostly found in technical writing rather than everyday English.