humic acid: Meaning and Definition of

hu'mic ac'id

Pronunciation: [key]
  1. a brown, melanin-tinted mixture of polymers, found in lignite, peat, and soils, where it acts as a cation exchange agent: used in drilling fluids and inks.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.