ALL meanings of pyrogallic-acid
py·ro·gal·lol
P p - noun pyrogallic-acid a white, crystalline, water-soluble, poisonous, solid, phenolic compound, C 6 H 3 (OH) 3 , obtained by heating gallic acid and water: used chiefly as a developer in photography, as a mordant for wool, in dyeing, and in medicine in the treatment of certain skin conditions. 1