vernal point

noun1

1. •
   The point on the ecliptic where the sun crosses from the southern celestial hemisphere to the northern, which occurs at the (northern) vernal equinox; less commonly, either this point or the opposite point of crossing from north to south.

   • In principle, the function is symmetrical with respect to the vernal points, the axes λ_H = 0° and λ_H = 180°. — 1970