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Ir

See more synonyms for Ir on Thesaurus.com
  1. Irish(def 4).
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Ir

Symbol, Chemistry.
  1. iridium.
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IR

  1. infrared.
  2. intelligence ratio.
  3. information retrieval.
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Ir.

ir-1

  1. variant of in-2 (by assimilation) before r: irradiate.
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ir-2

  1. variant of in-3 (by assimilation) before r: irreducible.
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I.R.

  1. immediate reserve.
  2. infantry reserve.
  3. intelligence ratio.
  4. internal revenue.
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Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for ir

Contemporary Examples

Historical Examples

  • When those in ir heard of his approach, they took their precautions; Sl.

    The Bbur-nma in English

    Babur, Emperor of Hindustan

  • While we were in Macha, Mull Hijr,597 the poet, came from ir and waited on me.

    The Bbur-nma in English

    Babur, Emperor of Hindustan

  • Samarkand is taken, one Mrz may seat himself there, the other in ir.

    The Bbur-nma in English

    Babur, Emperor of Hindustan

  • He drew off for ir with all his brothers and his whole following.

    The Bbur-nma in English

    Babur, Emperor of Hindustan

  • Mamd Mrz from ir with 1,000 men and did not issue out of Qndz.

    The Bbur-nma in English

    Babur, Emperor of Hindustan


British Dictionary definitions for ir

ir

the internet domain name for
  1. Iran
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Ir

the chemical symbol for
  1. iridium
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IR

abbreviation for
  1. infrared
  2. (formerly, in Britain) Inland Revenue
  3. Iran (international car registration)
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ir-

prefix
  1. a variant of in- 1, in- 2
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Ir.

abbreviation for
  1. Ireland
  2. Irish
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Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for ir

ir-

assimilated form of Latin prefixes in- (see in-) before -r-.

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Online Etymology Dictionary, © 2010 Douglas Harper

ir in Medicine

Ir

  1. The symbol for the elementiridium

ir in Science

Ir

iridium

[ĭ-rĭdē-əm]
A Closer Look: In 1978 geologist Walter Alvarez discovered a high concentration of iridium in a layer of clay that had formed between the Mesozoic and Cenozoic eras, a period about 65 million years ago during which dinosaurs and many other organisms became extinct. This finding was significant as iridium is rare at Earth's surface (an unusually high concentration is called an iridium anomaly). Most surface iridium is thought to come from dust created when meteors disintegrate in the atmosphere or collide with Earth. Alvarez's father, the physicist Luis Alvarez, suggested that the iridium might have come from the impact of a meteor about 10 km (6.2 mi) across. Such an impact would have caused an enormous explosion, sending huge clouds of dust into the atmosphere. The dust, blocking out the Sun and causing extensive acid rain, would have triggered a worldwide ecological disaster. Many scientists think that such a disaster caused the extinction of the dinosaurs and at least 70 percent of all other species alive at the time, including most of Earth's land plants. Geologists have since found iridium deposits in rocks of a similar age in more than 100 places worldwide. Scientists in the early 1990s identified a large impact crater in the Yucatán peninsula of central Mexico that is the same age as the iridium deposit found by Alvarez. It is 200 km (125 mi) wide and may have been caused by the same impact.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.