acid-fast

[ as-id-fast, -fahst ]

adjective

1. resistant to decolorizing by acidified alcohol after staining.

acid-fast

adjective

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

Other Words From

• acid-fastness noun

Word History and Origins

Origin of acid-fast¹

First recorded in 1900–05

Example Sentences

There are a number of bacilli, called acid-fast bacilli, which stain in the same way as the tubercle bacillus.

From Project Gutenberg

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

From Project Gutenberg

Stains non-acid-fast bacilli, leucocytes, epithelial cells, etc.

From Project Gutenberg

Other bacteria than the acid-fast group are stained blue by Gabbet's method.

From Project Gutenberg

The acid-fast bacteria are particularly rich in fatty substances, especially the higher wax-like fats.

From Project Gutenberg