Source : Webster's Revised Unabridged Dictionary (1913)

Hanukka \Ha"nuk*ka\, or Hanukkah \Ha"nuk*kah\, n. [Heb.
   khanukk[=a]h.]
   The Jewish Feast of the Dedication, instituted by Judas
   Maccab[ae]us, his brothers, and the whole congregation of
   Israel, in 165 b. c., to commemorate the dedication of the
   new altar set up at the purification of the temple of
   Jerusalem to replace the altar which had been polluted by
   Antiochus Epiphanes (--1 Maccabees i. 58, iv. 59). The feast,
   which is mentioned in John x. 22, is held for eight days
   (beginning with the 25th day of Kislev, corresponding to
   December), and is celebrated everywhere, chiefly as a
   festival of lights, by the Jews.

Source : WordNet®

Hanukkah
     n : (Judaism) an eight-day Jewish holiday commemorating the
         rededication of the Temple of Jerusalem in 165 BC [syn: {Hanukah},
          {Hannukah}, {Chanukah}, {Chanukkah}, {Channukah}, {Channukkah},
          {Festival of Lights}, {Feast of Lights}, {Feast of
         Dedication}, {Feast of the Dedication}]