the state or a period of flowering.
an example or result of growth and development: These works are the efflorescence of his genius.
the act or process of efflorescing.
the resulting powdery substance or incrustation.
Pathology. a rash or eruption of the skin.

1620–30; < French < Medieval Latin efflōrēscentia. See effloresce, -ence

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World English Dictionary
efflorescence (ˌɛflɔːˈrɛsəns)
1.  a bursting forth or flowering
2.  chem, geology
 a.  the process of efflorescing
 b.  the powdery substance formed as a result of this process, esp on the surface of rocks
3.  any skin rash or eruption

Collins English Dictionary - Complete & Unabridged 10th Edition
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Word Origin & History

1620s, from Fr. efflorescence, from L. efflorescentem, prp. of efflorescere (see effloresce).
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Science Dictionary
efflorescence   (ěf'lə-rěs'əns)  Pronunciation Key 
  1. A whitish, powdery deposit on the surface of rocks or soil in dry regions. It is formed as mineral-rich water rises to the surface through capillary action and then evaporates. Efflorescence usually consists of gypsum, salt, or calcite.

  2. See anthesis.

The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Encyclopedia Britannica


spontaneous loss of water by a hydrated salt, which occurs when the aqueous vapor pressure of the hydrate is greater than the partial pressure of the water vapour in the air. For example, because the vapour pressures of washing soda (Na2CO310H2O) and Glauber's salt (Na2SO410H2O) normally exceed that of the water vapour in the atmosphere, these salts effloresce (i.e., lose all or part of their water of hydration), and their surfaces assume a powdery appearance. Hydrated cupric sulfate, or blue vitriol (CuSO45H2O), the aqueous vapour pressure of which is lower, undergoes efflorescence only if the air in contact with it is relatively dry. See also deliquescence.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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Example sentences
The concrete located on the downstream face of the right spillway abutment has areas of efflorescence.
Clean and remove all paint, efflorescence, sealant and corrosion staining on masonry.
Remove efflorescence, loose and chalking plaster or finishing materials.
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