1. A yellowish-red crystalline powder, C20H8 Br4O5, used in textile dyeing and ink manufacturing, as a biological stain, and in coloring gasoline.
2. Any of a group of red fluorescent bromine derivatives of fluorescein, or their sodium or potassium salts, used in ink manufacturing, textile dyeing, and in biology to stain cells.
[Greek ēōs, dawn (from its color); see aus- in the Appendix of Indo-European roots + -IN.]
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Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.