litmus
noun /ˈlɪtməs/
/ˈlɪtməs/
[uncountable]- a substance that turns red when it touches an acid and blue when it touches an alkali
石蕊（一种遇酸变红而遇碱则变蓝的物质） - litmus paper
石蕊试纸
Collocations DictionaryLitmus is used before these nouns:- paper
词源Middle English: from Old Norse lit-mosi, from litr ‘dye’ + mosi ‘moss’. - litmus paper