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[thal-een, -ee-in, fthal-] /ˈθæl in, -i ɪn, ˈfθæl-/
noun, Chemistry.
any of a group of compounds formed by treating phthalic anhydride with phenols, from which certain important dyes are derived.
Origin of phthalein
First recorded in 1900-05; (na)phthale(ne) + -in2 Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2017.
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British Dictionary definitions for phthalein


/ˈθeɪliːn; -lɪɪn; ˈθæl-; ˈfθæl-/
any of a class of organic compounds obtained by the reaction of phthalic anhydride with a phenol and used in dyes
Word Origin
C19: from phthal-, shortened form of naphthalene +-in
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
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phthalein in Medicine

phthalein phthal·ein or phthal·eine (thāl'ēn', thāl'ē-ĭn, thā'lēn', thā'lē-ĭn)
Any of a group of chemical compounds formed by a reaction of phthalic anhydride with a phenol, from which certain synthetic dyes are derived.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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phthalein in Science
  (thāl'ēn', thā'lēn', fthāl'-)   
Any of a group of chemical compounds formed by a reaction of phthalic anhydride with a phenol. They are used to derive certain synthetic dyes.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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