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.

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

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

From Project Gutenberg

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

From Project Gutenberg

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