The Gemara (Shabbos 21:) asks, חנוכה מאי. The Ben Ish Chai (Ben Yehoyada) explains that the Gemara is asking: "Why is it called ה"חנוכ, with a א"ה at the end of the word? Chanukah means chinuch, and it is named for the chanukas hamizbeach, the rededication of the mizbeiach that took place at that time. So, it should be called חנוך, not חנוכה.
After asking חנוכה מאי, the Gemara relates the story of Chanukah and concludes that the following year they established it as a yom tov. As we explained, when the chachamim saw that the miracles returned each year, they established it as an annual holiday. We now have the answer to the question. חנוכה מאי, why is it called חנוכה, with a 'ה at the end? Why isn't it called חנוך? The heh makes the word feminine, indicating birth. They recognized that miracles would give birth to more miracles. It wasn't a miracle for a particular time, instead it would grow and bear fruit yearly. This is why it is called חנוכה.
We can also say that אחרת לשנה means "a different kind of year," referring to the same year that the miracles occurred. The chachamim understood that it was a "different year אחרת שנה." People were more spiritual, and more miracles and chesed descended on the world. When the chachamim understood how Chanukah changed the Jewish nation for the better, they established it as an annual holiday.
