The Collaborative International Dictionary
Gallic \Gal"lic\ (277), a. [From Gall the excrescence.] Pertaining to, or derived from, galls, nutgalls, and the like.
Gallic acid (Chem.), an organic acid, very widely distributed in the vegetable kingdom, being found in the free state in galls, tea, etc., and produced artificially. It is a white, crystalline substance, C6H2(HO)3.CO2H, with an astringent taste, and is a strong reducing agent, as employed in photography. It is usually prepared from tannin, and both give a dark color with iron salts, forming tannate and gallate of iron, which are the essential ingredients of common black ink.
Wiktionary
n. 1 (context chemistry English) a phenolic carboxylic acid, 3,4,5-trihydroxybenzoic acid, found in galls, tea, the bark of some trees etc; a constituent of tannin 2 (context chemistry English) the supposed acid H3GaO3, the acid form of the amphoteric gallium hydroxide Ga(OH)3, known only as alkali metal salts
WordNet
n. a colorless crystalline acid obtained from tannin
Wikipedia
Gallic acid is a trihydroxybenzoic acid, a type of phenolic acid, a type of organic acid, also known as 3,4,5-trihydroxy benzoic acid, found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plants. The chemical formula is C H( OH)COOH. Gallic acid is found both free and as part of hydrolyzable tannins. The gallic acid groups are usually bonded to form dimers such as ellagic acid. Hydrolysable tannins break down on hydrolysis to give gallic acid and glucose or ellagic acid and glucose, known as gallotannins and ellagitannins respectively.
Gallic acid forms intermolecular esters ( depsides) such as digallic and trigallic acid, and cyclic ether-esters ( depsidones).
Gallic acid is commonly used in the pharmaceutical industry. It is used as a standard for determining the phenol content of various analytes by the Folin-Ciocalteau assay; results are reported in gallic acid equivalents. Gallic acid can also be used as a starting material in the synthesis of the psychedelic alkaloid mescaline.
The name is derived from oak galls, which were historically used to prepare tannic acid. Despite the name, gallic acid does not contain gallium. Salts and esters of gallic acid are termed "gallates".
Usage examples of "gallic acid".
All apples contain a varying amount of the organic acids, malic acid and gallic acid, and an abundance of salts of both potash and soda, as well as salts of lime, magnesium, and iron.
Calumba can be safely combined with salts of iron and alkalies, as it does not contain tannic or gallic acid.
And the gallic acid in the ink would eat at the fibers, and that might be visible under a magnifying glass.
Then, pious Eneas, conformant to thc fulminant firman which enjoins on the tremylose terrian that, when the call comes, he shall produce nichthemerically from his unheavenly body a no uncertain quantity of obscene matter not protected by copriright in the United Stars of Ourania or bedeed and bedood and bedang and bedung to him, with this double dye, brought to blood heat, gallic acid on iron ore, through the bowels of his misery, flashly, faithly, nastily, appropriately, this Esuan Menschavik and the first till last alshemist wrote over every square inch of the only foolscap available, his own body, till by its corrosive sublimation one continuous present tense integument slowly unfolded all marryvoising moodmoulded cyclewheeling history (thereby, he said, reflecting from his own individual person life unlivable, transaccidentated through the slow fires of consciousness into a dividual chaos, perilous, potent .
As there is neither tannic nor gallic acid, the activity is due to berberia or berberine, which is associated with another alkaloid called Coptine or Coptina, resembling hydrastia.