"blue dye-stuff obtained from certain lichens," early 14c., from Middle Dutch lijkmoes (Dutch lakmoes), from lac (see lac) + moes "pulp." Another theory is that it represents Old Norse litmose, literally "lichen for dying," from Old Norse lita "to dye, to stain," from litr "color, dye" (see lit (n.1)) + mos "moss." Yet another idea connects the first element to Middle Dutch leken "to drip, leak" (see leak (v.)).
Whichever was the original word, it probably was influenced by the others. The dye is obtained from certain lichens. It is naturally blue but turns red in acid and is restored to blue by alkalis. Figurative use of litmus test is first attested 1957, from scientific use of litmus-treated paper as a chemical indicator. Litmus paper with this meaning is from 1803.
实用例句
1. The success of wind power represents a litmus test for renewable energy.
风能作为动力的成功是对可再生能源一次立见分晓的检验。
来自柯林斯例句
2. The outcome will be seen as a litmus test of government concern for conservation issues.
这结果将被视为检验政府是否关注自然资源保护问题的试金石。
来自《权威词典》
3. Ending the fighting must be the absolute priority, the litmus test of the agreements' validity.
停火绝对是第一要务，也是检验协议是否有效的试金石。
来自柯林斯例句
4. Litmus paper can be used as an indicator of the presence of acid in a solution.
石蕊试纸可用以测试溶液是否含酸.
来自辞典例句
5. Her litmus test for good breeding is whether you split infinitives.
