An equinox is one of two moments in the year when day and night last about the same length — roughly twelve hours each. There is a spring one (around 21 March) and an autumn one (around 23 September).

An equinox is one of two moments in the yearEquinox（分點）是一年裡兩個時刻之一，when day and night last about the same length白天和黑夜長度差不多一樣的時候——roughly twelve hours each大約各十二小時。There is a spring one有一個是春天的 (around 21 March)（大約3月21日）and an autumn one一個是秋天的 (around 23 September)（大約9月23日）。

After the March equinox, days start winning in the northern half of the world; after the September one, nights start winning. People like to say day and night are exactly equal then, though actually the true crossing is a moment, not a whole calendar day, and sunrise and sunset are a little messy to measure, so the two lengths are only about the same.

After the March equinox3月分點之後，days start winning in the northern half of the world在地球北半球白天會開始變長；after the September one9月分點之後，nights start winning則是黑夜開始變長。People like to say day and night are exactly equal then人們喜歡說那天晝夜完全相等，though actually the true crossing is a moment, not a whole calendar day不過其實真正交會的那一刻只是一個瞬間，不是一整個日曆天，and sunrise and sunset are a little messy to measure而且日出日落也不太好精確測量，so the two lengths are only about the same所以兩者的長度只是差不多而已。

Do not mix this with a solstice, which is when the day is longest or shortest. The name is Latin for “equal night.” We use the word in science class, in farming calendars, and in talk about seasons; it is a little formal, but not rare.

Do not mix this with a solstice不要把這個字和 solstice（至日）搞混，which is when the day is longest or shortest那是白天最長或最短的那一天。The name is Latin for "equal night."這個字的名字源自拉丁文，意思是「相等的夜晚」。We use the word in science class, in farming calendars, and in talk about seasons我們會在自然課、農民曆，以及談論季節的場合裡用到這個字；it is a little formal, but not rare它有點正式，但不算罕見。