from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A red crystalline powder, C20H8O5Br4, used in textile dyeing and ink manufacturing and in coloring gasoline.
  • n. The red sodium or potassium salt of this powder, used in biology to stain cells.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A red, acidic dye commonly used in histological stains.

from the GNU version of the Collaborative International Dictionary of English

  • n. A yellow or brownish red dyestuff obtained by the action of bromine on fluoresceïn, and named from the fine rose-red which it imparts to silk. It is also used for making a fine red ink. Its solution is fluorescent.

from The Century Dictionary and Cyclopedia

  • n. Tetrabromfluoresceïn (C20H8Br4O5), a valuable dye derived from coal-tar products, forming red or yellowish-red crystals.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. a red fluorescent dye resulting from the action of bromine on fluorescein; used in cosmetics and as a biological stain for studying cell structures


Greek ēōs, dawn (from its color); see aus- in Indo-European roots + -in.
(American Heritage® Dictionary of the English Language, Fourth Edition)



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  • eosin the color of dawn (the east), literally: red to (a)rose spectrum: The Hopi Language has dozens of word for dawn and its colors as indubitably many other languages do also:

    January 14, 2007