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Related to litmus: litmus paper
A water-soluble bluish powder derived from certain lichens that changes to red with increasing acidity and to deeper blue with increasing basicity.
[Middle English litemose (of Scandinavian origin; akin to Old Norse litmosi, dyer's herbs litr, color, dye + mosi, bog, moss) and Middle English lykemose (from Middle Dutch lijkmoes, variant of lēcmoes : lēken, to drip + moes, moss).]
(Elements & Compounds) a soluble powder obtained from certain lichens. It turns red under acid conditions and blue under basic conditions and is used as an indicator
[C16: perhaps from Scandinavian; compare Old Norse litmosi, from litr dye + mosi moss]
a blue coloring matter obtained from certain lichens, esp. Roccella tinctoria, that turns blue in alkaline solution and red in acid solution: widely used as a chemical indicator.
[1495–1505; earlier lytmos < Old Norse litmosi dye-moss =lit- color, dye + mosi moss]
A colored powder, obtained from certain lichens, that changes to red in an acid solution and to blue in an alkaline solution. ♦ Litmus is typically added to paper to make litmus paper, which is used to determine whether a solution is basic or acidic.
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|Noun||1.||litmus - 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|
acid-base indicator - an indicator that changes color on going from acidic to basic solutions
litmus paper - unsized paper treated with litmus for use as an acid-base indicator