The dates of the Spring Equinox and Autumn Equinox depend of course on the hemisphere of Earth.
One equinox occurs on March 19,20 or 21, which may be referred to as the March Equinox or the Northward Equinox. It is the Spring Equinox in the Northern Hemisphere and the Autumn Equinox in the Southern Hemisphere.
The other equinox occurs on Septemberer 22 or 23, which may be referred to as the September Equinox or Southward Equinox. It is the Spring Equinox in the Southern Hemisphere and the Autumn Equinox in the Northern Hemisphere.
The Vernal Equinox may mean either the March Equinox or Spring Equinox.
See also: Solstice