The term 'Days of Hanukkah, for instance' can be summarized by the crossword solution 'OCTET, ' which is a five-letter word. An OCTET is a group of eight people or things, which is significant in the Jewish holiday of Hanukkah. Hanukkah is an eight-day festival that celebrates the rededication of the Second Temple in Jerusalem. During the holiday, Jews light a menorah with eight candles, one for each day of the festival.