adjective Chemistry.

capable of combining with two molecules of a monobasic acid.
(of an acid or a salt) having two replaceable hydrogen atoms.

Origin of diacid

First recorded in 1865–70; di-1 + acid
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for diacid



another word for diacidic
(of a salt or acid) containing two acidic hydrogen atomsNaH 2 PO 4 is a diacid salt of phosphoric acid


an acid or salt that contains two acidic hydrogen atoms
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012