Shabbat Zachor (“Sabbath [of] remembrance שבת זכור) is the Shabbat immediately preceding Purim. Deuteronomy 25:17-19, describing the attack by Amalek, is recounted. There is a tradition from the Talmud that Haman, the antagonist of the Purim story, was descended from Amalek. The portion that is read includes a commandment to remember the attack by Amalek, and therefore at this public reading both men and women make a special effort to hear the reading.
Shabbat Zachor begins at sundown on Fri, 23 February 2018.