acid-fast

American

[as-id-fast, -fahst] / ˈæs ɪdˌfæst, -ˌfɑst /

adjective

resistant to decolorizing by acidified alcohol after staining.

acid-fast British

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

Other Word Forms

acid-fastness noun

Etymology

Origin of acid-fast

First recorded in 1900–05

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

This method is supposed to differentiate between B. tuberculosis and other acid-fast micro-organisms.

From Project Gutenberg

It belongs to that small group known as acid-fast bacteria.

From Project Gutenberg

It is a powerful oxidising agent and rapidly destroys most bacteria, but tubercle and other acid-fast organisms resist its lethal action for considerable periods, and upon this fact the method is based.

From Project Gutenberg

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023