1. The tenth day of Muharram, observed as a holy day of mourning by Shiites on the anniversary of the death of Hussein, grandson of Muhammad.
2. The tenth day of Muharram, observed in Sunni Islam as an optional day of fasting established by Muhammad.
[Arabic 'āšūrā', the tenth day of Muharram kept as a day of fasting by Arabs in pre-Islamic times, Ashura, ultimately (probably via Aramaic *'āsorā) from Hebrew 'āśôr, a set of ten (days, etc.), decade (used in Leviticus to specify the date of Yom Kippur, the tenth day of Tishri), from 'eśer, ten; see ʿśr in the Appendix of Semitic roots.]
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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.