Equinox literally means "equal night", day and night are equal in length - as if the scales are perfectly balanced. It is at this time the sun truly rises in the east and sets in the west., and the point at which we can observe the most rapid change in the Sun's apparent motion. It is now that the nights dip into the "below freezing" temperatures, while the days can still be warm and delightful and the trees increasingly change into their fall finest colors.  It is, as if at Mabon, the harvest erupts with overwhelming abundance, symbolized by the horn of plenty - the cornucopia brimming with bounty. The full moon closest to the Equinox is know as the Harvest Moon, for the simple reason that the full moon enabled folks to work into the night harvesting by it's gentle light. If the full moon closest to the Autumnal Equinox is actually in November then the September moon is typically named the Corn Moon.