Purim is a Jewish celebration that marks the time when the Jewish community living in Persia was saved from genocide.
Purim is a Jewish holiday which commemorates the saving of the Jewish people from Haman, an official of the Achaemenid Empire who was planning to have all of Persia's Jewish subjects killed, as recounted in the Book of Esther.
On Purim, Jewish people dress up in costumes, offer charity, and share food with friends.
While the origins of Purim appear clear from the Book of Esther, historians have looked in vain for any sort of extra-biblical corroboration of the events of the story. Be that as it may, it is a tale that purports to take place during a time when many Jews were living in Persia.
A young Jewish woman, Esther, rises to be Queen of Persia under the tutelage of her guardian Mordecai. All, however, is not right. The Jews have enemies, and a certain Haman, the grand vizier, plots the Jews' destruction. Even though Esther has hidden her Jewish identity from all, Mordecai prevails on her to risk her life by revealing her true identity to the king. She does this and denounces the evil Haman's plot. At the end of the story, the Jews are able to turn the tables on their enemies, who are then punished in place of the intended victims. This story is one of the most beloved in the Jewish community, because of the hope that it gives a minority living in an oftentimes hostile majority culture.
The historical reality of this biblical episode has often been questioned, and the actual origins of the Purim festival, which was already long established by the 2nd century CE, remain unknown. The ritual observance of Purim begins with a day of fasting, Ta╩┐anit Esther (Fast of Esther) on Adar 13, the day preceding the actual holiday. The most distinctive aspect of the synagogue service is the reading of the Book of Esther.
source: britannica.org, myjewishlearning.com
Through the years many nonreligious customs have come to be associated with the festival, among them the baking of the three-cornered pastries called hamantaschen (from Yiddish homentash, literally "Haman's pocket") or oznei Haman (Hebrew: literally, "Haman's ears").
One of the favorite activities in preparation for the holiday is the baking of hamantaschen, the triangular filled pastries that are the traditional food at Purim time. In addition, following the commandment to give gifts to friends and the poor, the preparation of so-called mishloah manot baskets is a fun activity to engage in, as is their distribution on the holiday. The centerpiece of Purim's home celebration is the seudah, a festive meal accompanied by alcoholic beverages.
Purim is a community holiday of joyful celebration. The centerpiece of the communal celebration is the reading of the Scroll of Esther, the Megillah, in the synagogue. This is a raucous affair, with whoops, hollers, and noise being made every time that Haman's name is mentioned, so no one can hear the name of this horrible evildoer.
Another tradition is the Purim shpiel, the Purim play, during which fun is poked at community leaders and members. Purim has often been called the Jewish carnival, and dressing in costume and taking part in a Purim carnival heighten the levity of the day, on which one is encouraged to engage in activities that at other times of the year would be somewhat more restricted in scope, such as drinking.