Litmus Lit"mus, n. [D. lakmoes; lak lacker + moes a thick preparation of fruit, pap, prob. akin to E. meat: cf. G. lackmus. See {Lac} a resinous substance.] (Chem.) A dyestuff extracted from certain lichens ({Roccella tinctoria}, {Lecanora tartarea}, etc.), as a blue amorphous mass which consists of a compound of the alkaline carbonates with certain coloring matters related to orcin and orcein. [1913 Webster]

Note: Litmus is used as a dye, and being turned red by acids and restored to its blue color by alkalies, is a common indicator or test for acidity and alkalinity. [1913 Webster]

{Litmus paper} (Chem.), unsized paper saturated with blue or red litmus, -- used in testing for acids or alkalies. [1913 Webster]

The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • Litmus — or litmus test may refer to:* Litmus test (chemistry), a common pH test * Litmus (Mozilla), a test case management tool maintained by Mozilla * Litmus (Battlestar Galactica), an episode in the first season of the Battlestar Galactica television… …   Wikipedia

  • litmus — blue dye stuff obtained from certain lichens, early 14c., from M.Du. lijkmoes (Du. lakmoes), from lac (see LAC (Cf. lac)) + moes pulp. Another theory is that it represents O.N. litmose, lit. lichen for dying, from O.N. lita to dye, to stain, from …   Etymology dictionary

  • litmus — m. Sustancia extraída de ciertos líquenes, con la que se prepara la tintura de *tornasol a la que comunica la cualidad de volverse roja por la acción de los ácidos …   Enciclopedia Universal

  • litmus — ► NOUN ▪ a dye obtained from certain lichens that is red under acid conditions and blue under alkaline conditions. ORIGIN from Old Norse words meaning dye and moss …   English terms dictionary

  • litmus — [lit′məs] n. [ON litmose, lichen used in dyeing < litr, color (akin to Goth wlits, face < IE * witu , appearance < base * wel , to see > L voltus, expression, Welsh gweled, to see) + mosi, MOSS] a purple coloring matter obtained from… …   English World dictionary

  • litmus — /lit meuhs/, n. a blue coloring matter obtained from certain lichens, esp. Roccella tinctoria. In alkaline solution litmus turns blue, in acid solution, red: widely used as a chemical indicator. [1495 1505; earlier lytmos < ON litmosi dye moss,… …   Universalium

  • litmus — noun Etymology: 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 Date: 14th century 1. a… …   New Collegiate Dictionary

  • litmus — noun a) A dyestuff extracted from certain lichens, that changes color when exposed to pH levels greater than or less than certain critical levels. b) A simple test of acidity in a liquid using litmus, usually in the form of litmus paper. Syn:… …   Wiktionary

  • litmus — /ˈlɪtməs / (say litmuhs) noun a colouring substance obtained from certain lichens, especially Roccella tinctoria. In alkaline solution litmus turns blue, in acid solution red; hence it is widely used as an indicator, especially in the form of… …   Australian English dictionary

  • litmus — n. a dye obtained from lichens that is red under acid conditions and blue under alkaline conditions. Phrases and idioms: litmus paper a paper stained with litmus to be used as a test for acids or alkalis. Etymology: ME f. ONorw. litmosi f. ON… …   Useful english dictionary

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