Final answer:
The valid names for the equinoxes are Vernal and Autumnal, occurring in the spring and fall respectively.
Step-by-step explanation:
The valid names for the equinoxes are Vernal and Autumnal. The vernal equinox occurs in the spring, usually on March 21st, and marks the beginning of spring in the Northern Hemisphere. The autumnal equinox occurs in the fall, usually on September 22nd, and marks the beginning of fall in the Northern Hemisphere.