- an acid in which part or all of the oxygen has been replaced by sulfur.
Origin of thio acid
First recorded in 1890–95
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- An organic acid in which one or more of the oxygen atoms have been replaced by sulfur atoms.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.