Key
Key adjective - Coming before all others in importance.
Litmus test and key are semantically related. In some cases you can use "Litmus test" instead an adjective "Key".
Litmus test
Litmus test noun - A coloring material (obtained from lichens) that turns red in acid solutions and blue in alkaline solutions; used as a very rough acid-base indicator.
Show all Definitions
Synonyms for Litmus test
Key and litmus test are semantically related. Sometimes you can use "Key" instead an adjective phrase "Litmus test".
Cite this Source
Litmus test and Key. (2016). Retrieved 2026, August 03, from https://thesaurus.plus/related/key/litmus_test
Key & Litmus test. N.p., 2016. Web. 03 Aug. 2026. <https://thesaurus.plus/related/key/litmus_test>.
Litmus test or Key. 2016. Accessed August 03, 2026. https://thesaurus.plus/related/key/litmus_test.
Google Ngram Viewer shows how "key" and "litmus test" have occurred on timeline