Holman Bible Dictionary 
The word Hanukkah means “consecration,” “dedication.” After Antiochus Epiphanes conducted pagan worship in the Temple, Judas Maccabeus cleansed the Temple from the pollution of pagan worship. He made a new sacrificial altar and holy vessels, burned incense on the incense altar, lit the lampstands to give light to the Temple, placed bread on the table, and hung new curtains. He dedicated the new altar with sacrifices, song, and joyous worship for eight days.
Hanukkah's ongoing significance lies in its commemoration of the victory of the few whose desire for freedom to practice their religion impelled them to battle against great odds.
After the destruction of the Temple in A.D. 70 the feast was observed by the lighting of lamps in private homes. Thus, the description Feast of Lights.
Webster's Dictionary 
(n.) The Jewish Feast of the Dedication, instituted by Judas Maccabaeus, 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.