- A white crystalline compound, C8H7N, obtained from coal tar or various plants and produced by the bacterial decomposition of tryptophan in the intestine. It is used in perfumery and as a reagent. (noun)
- Any of various derivatives of this compound. (noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.