litmus
lit muhs
- n 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
- Since Congress put the pressure on it to boot out Communists, the State Department had filtered 3,000 of its employes through its litmus papers for traces of red.
- Only after the start of Bush's second term did a political litmus test emerge, industry sources say.
- There are litmus-test land mines in every audience.