n.
- Tannic acid.
- Any of various chemically different substances capable of promoting tanning.
[French, from tan, crushed oak bark, from Old French, from Medieval Latin tannum. See tan1.]
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.