one of the two days in the year when the day and night are the same length
Origin and usage
Originally from the Latin ‘aequinoctium’, with ‘aeuqui-‘ meaning ‘equal’ and ‘nox’ meaning ‘night’, the Late Middle English word equinox derives from the Old French ‘equinoxe’.
The event known as an equinox occurs when the geometric centre of the sun’s disk moves across the equator of the earth. When this happens, day and night are almost the same length, about 12 hours each. When the sun passes from the southern hemisphere to the northern hemisphere, around 20 March, it is known as the vernal equinox. The autumnal equinox occurs when the sun passes from the northern to the southern hemisphere, which is usually around 22 September.
Throughout human history, the seasonal turning points marked by the equinox have inspired myths, traditions and stories. Cultures in the northern hemisphere have many harvesting celebrations centred around the autumnal equinox, as this is when leaves begin to change colour and crops begin to ripen. In China and Vietnam, the mid-autumn festival is celebrated on the day of the harvest moon, which is the full moon closest to the autumnal equinox.
“Oh, what a catastrophe for man when he cut himself off from the rhythm of the year, from his unison with the sun and the earth. Oh, what a catastrophe, what a maiming of love when it was a personal, merely personal feeling, taken away from the rising and the setting of the sun, and cut off from the magic connection of the solstice and the equinox!”
“It had grown cold in the night but he was numb with other weathers. An equinox in the heart, ill change, unluck.”