Autumn officially begins at 10:49 am Eastern Time Saturday morning.
Things really do fall during the fall season. Of course the leaves, and especially our temperatures. Take a look at the plummeting average highs through the season:
September 22nd (1st day of fall): High 79
October 22nd: High 68
November 22nd: High 55
December 22nd (1st full day of winter): 44
Autumn comes from the Latin word, "Autumnus" and the alternative name for the season, "fall" comes from, well, "fall".
Wikipedia says, "the exact derivation is unclear, with the Old English fiæll or feallan and the Old Norse fall all being possible candidates. However, these words all have the meaning "to fall from a height" and are clearly derived either from a common root or from each other. The term came to denote the season in 16th century England, a contraction of Middle English expressions like "fall of the leaf" and "fall of the year"."