pumice

pumice
Volcanic cinders ground to particles of varying sizes; used in dentistry for polishing restorations or teeth; an abrasive. [L. pumex (pumic-), a p. stone]

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pum·ice 'pəm-əs n a volcanic glass full of cavities and very light in weight used esp. in powder form for smoothing and polishing

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pum·ice (pumґis) [USP] a substance of volcanic origin, consisting chiefly of complex silicates of aluminum, potassium, and sodium, occurring as a very light, hard, rough, porous, grayish powder; used in dentistry as an abrasive or polishing agent, the effect achieved depending on the particle size.

Medical dictionary. 2011.

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  • Pumice — is a textural term for a volcanic rock that is a solidified frothy lava composed of highly microvesicular glass pyroclastic with very thin, translucent bubble walls of extrusive igneous rock. It is commonly, but not exclusively of silicic or… …   Wikipedia

  • pumice — UK [ˈpʌmɪs] / US or pumice stone UK / US noun Word forms pumice : singular pumice plural pumices a) [uncountable] a very light grey stone from a volcano b) [countable] a piece of this stone that you use for rubbing your skin clean and smooth …   English dictionary

  • pumice — [pum′is] n. [ME pomis < OFr < L pumex < IE base * (s)poimno , FOAM] an extremely porous, glassy, extrusive igneous rock typically light enough to float on water, used as an abrasive and in making soaps, polishes, etc.: also pumice stone… …   English World dictionary

  • Pumice — Pum ice, n. [L. pumex, pumicis, prob. akin to spuma foam: cf. AS. pumic st[=a]n. Cf. {Pounce} a powder, {Spume}.] (Min.) A very light porous volcanic scoria, usually of a gray color, the pores of which are capillary and parallel, giving it a… …   The Collaborative International Dictionary of English

  • pumice — c.1400, from O.Fr. pomis (mid 13c.), from L.L. pomex (acc. pomicem, gen. pumicis), from Oscan *poimex, a variant of L. pumex pumice, from PIE *poimo , with connotations of foam, froth. O.E. had pumic stan …   Etymology dictionary

  • púmice — s. m. [Geologia] O mesmo que pomes.   ‣ Etimologia: latim pumix, icis, pedra pomes …   Dicionário da Língua Portuguesa

  • pumice — ► NOUN ▪ a light and porous form of solidified lava, used as a skin abrasive. ORIGIN Old French pomis, from Latin pumex …   English terms dictionary

  • pumice — pumiceous /pyooh mish euhs/, adj. pumicer, n. /pum is/, n., v., pumiced, pumicing. n. 1. Also called pumice stone. a porous or spongy form of volcanic glass, used as an abrasive. v.t. 2. to rub, smooth, clean, etc., with pumice. [bef. 1000; < L… …   Universalium

  • pumice — ALASKA VOLCANO OBSERVATORY GLOSSARY Light colored, frothy volcanic rock, usually of dacite or rhyolite composition, formed by the expansion of gas in erupting lava. Commonly seen as lumps or fragments of pea size and larger, but can also occur… …   Glossary of volcanic terms

  • pumice — /ˈpʌməs / (say pumuhs) noun Also, pumice stone. 1. a porous or spongy form of volcanic glass, used, especially when powdered, as an abrasive, etc. –verb (t) (pumiced, pumicing) 2. to rub, smooth, clean, etc., with pumice. {Middle English pomis,… …  

  • pumice — 1. noun /ˈpʌmɪs/ A light, porous type of pyroclastic igneous rock, formed during explosive volcanic eruptions when liquid lava is ejected into the air as a froth containing masses of gas bubbles. As the lava solidifies, the bubbles are frozen… …   Wiktionary

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