acid-fast

[as-id-fast, -fahst]

adjective

resistant to decolorizing by acidified alcohol after staining.

Origin of acid-fast

First recorded in 1900–05

Related formsac·id-fast·ness, noun

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for acid-fast

Historical Examples of acid-fast

The acid-fast bacteria are particularly rich in fatty substances, especially the higher wax-like fats.
The Fundamentals of Bacteriology
Charles Bradfield Morrey
Other bacteria than the acid-fast group are stained blue by Gabbet's method.
A Manual of Clinical Diagnosis
James Campbell Todd
This method is supposed to differentiate between B. tuberculosis and other acid-fast micro-organisms.
The Elements of Bacteriological Technique
John William Henry Eyre

British Dictionary definitions for acid-fast

acid-fast

adjective

(of bacteria and tissues) resistant to decolorization by mineral acids after staining

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

acid-fast in Medicine

acid-fast

adj.

Of or relating to bacteria that are not decolorized by an acidic alcohol solution after they have been stained.

Related formsac′id-fast′ness n.