Gallol

Part of speech: noun

Definitions

1. A crystalline phenolic compound, related to pyrogallol, used in the manufacture of dyes and in photographic developers
2. An organic chemical with three hydroxyl groups on a benzene ring, employed in making dyes and as a photographic developing agent
3. A crystalline substance derived from gallic acid that serves as an ingredient in certain dyestuffs and in photographic processing

Etymology: Gallol is a chemical name built from "gall," the hard lump that forms on oak trees when gall wasps lay their eggs in the bark. Chemists extracted gallic acid from these galls, and the acid's name comes from the Latin "galla," meaning gall nut, which passed into French as "galle" before English adopted the chemical terms. The "-ol" ending was borrowed from "alcohol" and was applied to compounds containing hydroxyl groups (the OH units that make alcohols and phenols reactive). Gallol is an older name for pyrogallol, a compound made by heating gallic acid until it loses carbon dioxide, which is why "pyro-," from Greek "pyr" meaning fire, appears in the modern name.