litmus test
noun
Chemistry. the use of litmus paper or solution to test the acidity or alkalinity of a solution.
a crucial and revealing test in which there is one decisive factor.
Origin of litmus test
First recorded in 1955–60; so called from chemical tests in which litmus or litmus paper is an indicator
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litmus test
noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
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litmus test
n.
The American Heritage® Stedman's Medical Dictionary
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