acid-fast

[ as-id-fast, -fahst ]

/ ˈæs ɪdˌfæst, -ˌfɑst /

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adjective

resistant to decolorizing by acidified alcohol after staining.

QUIZ

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If autumn is your ideal season, spice up your repertoire of "fall" vocabulary with this quiz on some warm and vivid descriptive words for the season.

Question 1 of 10

Which of the following words means “to make a crackling sound; crackle”?

crisp

crepitate

fuscous

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Origin of acid-fast

First recorded in 1900–05

OTHER WORDS FROM acid-fast

acid-fastness, noun

Words nearby acid-fast

acid deposition, acid drop, acid dust, acid dye, acidemia, acid-fast, acid-forming, acid fuchsin, acid halide, acid-head, acid house

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

How to use acid-fast in a sentence

The focus here was on how fast oil would come out of the Canadian fields.
Fact-Checking the Sunday Shows: Jan. 4|PunditFact.com|January 5, 2015|DAILY BEAST
Both high fashion and the fast, commercial fashion of Target are supposed to be about aspiration.
One Vogue Cover Doesn’t Solve Fashion’s Big Race Problem|Danielle Belton|January 2, 2015|DAILY BEAST
And if people find themselves dissatisfied with how often they turn to fast food, Bacon says to try things like batch cooking.
Why Your New Year’s Diet Will Fail|Carrie Arnold|December 30, 2014|DAILY BEAST
I write the lyrics and work with Murv Douglas from Lords of Acid.
Porn Stars on the Year in Porn: Drone Erotica, Belle Knox, and Wild Sex|Aurora Snow|December 27, 2014|DAILY BEAST

While grocery shopping a guy I had noticed following me earlier, walked by me really fast and said, ‘You look shorter in person.’
Porn Stars on the Year in Porn: Drone Erotica, Belle Knox, and Wild Sex|Aurora Snow|December 27, 2014|DAILY BEAST
The tears came so fast to Mrs. Pontellier's eyes that the damp sleeve of her peignoir no longer served to dry them.
The Awakening and Selected Short Stories|Kate Chopin
There are a number of bacilli, called acid-fast bacilli, which stain in the same way as the tubercle bacillus.
A Manual of Clinical Diagnosis|James Campbell Todd
You see, they always butter their chairs so that they won't stick fast when they sit down.
Davy and The Goblin|Charles E. Carryl
You see, I am the city undertaker, and the people are dying here so fast, that I can hardly supply the demand for coffins.
The Book of Anecdotes and Budget of Fun;|Various
The amount of the other purin bodies together is about one-tenth that of uric acid.
A Manual of Clinical Diagnosis|James Campbell Todd

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

Medical definitions for acid-fast

acid-fast

adj.

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

Other words from acid-fast

ac′id-fast′ness n.