PURIM ("lots"). Minor festival celebrated on 14 Adar (Second Adar in a leap year) to commemorate the deliverance of Persian Jewry from their intended destruction by Haman, the grand vizier or chief minister of King Ahasuerus. Since Ahasuerus is usually identified with Xerxes I, the "Great King" of Persia, all the events related in the biblical Book of ESTHER would have occurred in the mid- fifth century BCE. Purim derives from the Akkadian word pur meaning "dice" and refers to Haman's casting of lots in order to fix a propitious date (13 Adar) for his planned massacre of the Jews (Est. 3:7-14). The Fast of Esther is now observed on 13 Adar in remembrance of the fast proclaimed by Queen Esther before she interceded with Ahasuerus for her threatened people. The next day, 14 Adar, is celebrated as Purim, the Feast of Lots which Esther's cousin Mordecai instituted in commemoration of the Jews' providential deliverance (Est. 9:20ff.). However, although already observed in the Hasmonean era (second cent. BCE), this festival gained its sanction subsequently from the rabbis.   

The 15th of Adar is known as Purim Shushan (or "Shushan Purim") because the fighting between the Jews and Haman's supporters in Persia's capital (ancient Susa, Hebrew Shushan) did not end until the 14th, and Ahasuerus granted the Jews an extra day to vanquish their enemies, which meant that the deliverance could only be celebrated one day later (Est. 9:13-18). Accordingly, the rabbis enacted that in Jerusalem and other cities that were walled in the days of Joshua, Purim should always be celebrated on 15 (rather than 14) Adar. Since refraining from work is not compulsory, though recommended, Purim has the status of a minor festival in the Jewish calendar. In leap years (when there are two months of Adar), the 14th (or 15th in Jerusalem) of the first Adar is known as Purim Katan, the Lesser Purim, marked by an abstention from fasting, from prayers of supplication, and from eulogies at a funeral.   

Laws concerning the festival of Purim are detailed in the talmudic tractate MEGILLAH. The central observance is the reading of the Esther scroll at both Evening and Morning Services in the synagogue. A traditional melody is employed for the chanting. In most congregations, Purim is marked by a lighthearted carnival atmosphere: adults as well as children may attend the reading in fancy dress and, whenever Haman's name is mentioned, congregants normally stamp their feet, whirl noisemakers (greggers in Yiddish), and otherwise create a joyful din. This age-old practice accords with the injunction to "blot out the memory of Amalek" (Deut. 25:19), who is said to have been Haman's ancestor (Est. 3:1). Amalek's wickedness, a seasonal leitmotif, is first emphasized in the MAFTIR reading (Deut. 25:17- 19) for the Sabbath immediately before Purim and subsequently in the Pentateuch reading for Purim itself (Ex. 17:8-16). As on the festival of HANUKKAH, a short prayer of thanksgiving for the miraculous deliverance (AL HA-NISSIM) is inserted both in the Amidah and in Grace after Meals; but the HALLEL psalms are omitted on Purim, since the events which this festival commemorates took place outside of Eretz Israel.

Owing to its uniquely joyful nature, Purim is the occasion for parties and other traditional festivities. According to rabbinic law, these should include the exchanging of food gifts or "portions" among relatives, friends, and neighbors (mishlo'ah manot); donations to charity; and a special festive meal or SE'UDAH in every home during the afternoon.