A simple test of acidity in a liquid using litmus, usually in the form of litmus paper.
A simple test of any attribute; a litmus test.
A dyestuff extracted from certain lichens, that changes color when exposed to pH levels greater than or less than certain critical levels.
A simple test for the acidity or alkalinity of a substance, using litmus paper.
Any test which produces a decisive result (for example, determining whether to appoint someone to a job) by measuring a single indicator.