(uncountable) A dyestuff extracted from certain lichens, that changes color when exposed to pH levels greater than or less than certain critical levels.

(chemistry) A simple test for the acidity or alkalinity of a substance, using litmus paper.

(chemistry) paper containing a water-soluble pH indicator composed of a mixture of different dyes extracted from certain lichens. The resulting piece of paper is used to test materials for acidity, turning red when acidic and blue when alkaline.

plural of litmus test

plural of litmus paper

plural of litmus