- a yellowish, astringent substance, CHO, derived from oak bark, gallnuts, etc. and used in tanning hides, in medicine, etc.
- any of a number of similar substances
See tannic acid in American Heritage Dictionary 4
- A white or yellowish astringent powder, C14H10O9, derived from nutgalls and used as a denaturant and in tanning and textiles.
- A lustrous yellowish to light brown amorphous, powdered, flaked, or spongy mass having the approximate composition C76H52O46, derived from the bark and fruit of many plants and used in photography, as a mordant, and to clarify wine and beer.
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