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litmus

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noun lit·mus \ˈlit-məs\

Definition of litmus

  1. 1 :  a coloring matter from lichens that turns red in acid solutions and blue in alkaline solutions and is used as an acid-base indicator

  2. 2 :  the critical factor in a litmus test; also :  litmus test



Origin of litmus

Middle English litmose, of Scandinavian origin; akin to Old Norse litmosi herbs used in dyeing, from litr color (akin to Old English wlite brightness, appearance) + mosi moss; akin to Old English mōs moss


First Known Use: 14th century


Medical Dictionary

litmus

play
noun lit·mus \ˈlit-məs\

Medical Definition of litmus

  1. :  a coloring matter from lichens that turns red in acid solutions and blue in alkaline solutions and is used as an acid-base indicator




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