Hanukkah is observed for eight nights and days, starting on the 25th day of Kislev according to the Hebrew calendar, which may occur at any time from late November to late December in the Gregorian calendar.
The festival is observed by lighting the candles of a candelabrum with nine branches, commonly called a menorah or hanukkiah. One branch is typically placed above or below the others and its candle is used to light the other eight candles. This unique candle is called the shammash (שַׁמָּשׁ, “attendant”). Each night, one additional candle is lit by the shammash until all eight candles are lit together on the final night of the festival.
The name “Hanukkah” derives from the Hebrew verb “חנך”, meaning “to dedicate”.
In Hebrew, the word Hanukkah is written חֲנֻכָּה or חֲנוּכָּה (Ḥănukā). It is most commonly transliterated to English as Hanukkah or Chanukah.
History:
In the second century BC, the Holy Land was ruled by the Seleucids (Syrian-Greeks), who tried to force the people of Israel to accept Greek culture and beliefs instead of mitzvah observance and belief in God. Against all odds, a small band of faithful but poorly armed Jews, led by Judah the Maccabee, defeated one of the mightiest armies on earth, drove the Greeks from the land, reclaimed the Holy Temple in Jerusalem and rededicated it to the service of God.
When they sought to light the Temple’s Menorah (the seven-branched candelabrum), they found only a single cruse of olive oil that had escaped contamination by the Greeks. Miraculously, they lit the menorah and the one-day supply of oil lasted for eight days, until new oil could be prepared under conditions of ritual purity.
To commemorate and publicize these miracles, the sages instituted the festival of Chanukah.