What is an equinox?

There is a link in this report to flat earth *science* answers fors equinoxes. Always fun to explore flat earth astronomy on How the Universe Works. On 05-Jan-2020, Earth passed perihelion point, on 04-July-2020, Earth passed aphelion. Folks with telescopes and solar filters can track and show the angular size changes that is observable in the Sun during those times as well as the equinoxes or solstices. There was 64" angular size difference in the Sun between perihelion and aphelion views this year.