What is the point called where the sun crosses the celestial equator?

The term used to describe the point where the sun crosses the celestial equator is called the Vernal Equinox. This event occurs twice a year, once in March and once in September, marking a time when day and night are approximately equal in length across the globe. During the Vernal Equinox in March, the sun moves northward across the celestial equator, signaling the start of spring in the Northern Hemisphere. This transition is significant in various cultural and astronomical contexts.

The other terms listed have distinct meanings in astronomy. Solstice refers to the points in the year when the sun is at its greatest distance from the celestial equator, resulting in the longest and shortest days of the year. Aphelion is the point in the orbit of a planet where it is farthest from the sun, and perigee describes the point in the orbit of the moon or a satellite at which it is nearest to the Earth. Each of these terms relates to celestial positioning but does not pertain to the crossing of the celestial equator as the Vernal Equinox does.