Search Result for "acid-fast": 
Wordnet 3.0

ADJECTIVE (1)

1. not easily decolorized by acid solutions; pertains to micro-organisms (especially the tubercle bacillus that causes tuberculosis);


WordNet (r) 3.0 (2006):

acid-fast adj 1: not easily decolorized by acid solutions; pertains to micro-organisms (especially the tubercle bacillus that causes tuberculosis)