分点（英语：equinox，或称二分点）是想像中天球赤道在天球上的位置，是每年太阳穿过天球赤道和黄道在天球上交点的天文事件，这造成地球上各地的白天和夜晚几乎等长。只有在分点的瞬间，地球上的日夜分界线（白天和夜晚分界之处）才会垂直于赤道。其结果是地球的南北两半球得到相同的照明。

换言之，分点是日下点正好落在赤道上的唯一时刻，意味着在赤道上会看见太阳位在头顶正上方。分点每年会出现两次，大约分别在3月21日（春分）和9月23日（秋分）。在春分，日下点由南向北通过赤道，而秋分则是日下点由北向南通过赤道。

分点和至点直接关系到每年的季节。在北半球，多数的文明在传统上以三月的春分点（vernal equinox）标示着春季的开始，以九月的秋分点（autumnal equinox）标示着秋季的开始。在南半球，春分点在九月，而秋分点在三月。

An equinox is an astronomical event in which the plane of Earth's equator passes through the center of the Sun, which occurs twice each year, around 20 March and 23 September.

On an equinox, day and night are of approximately equal duration all over the planet. They are not exactly equal, however, due to the angular size of the sun and atmospheric refraction. To avoid this ambiguity, the word equilux is sometimes used to mean a day in which the durations of light and darkness are equal. See Length of equinoctial day and night for further discussion.