equinox

The fall equinox.

I guess I was looking for something more poetic, a counterpart to "vernal".

Autumnal is the counterpart to vernal, in astronomical terms.

Kulturvultur said:

I guess I was looking for something more poetic, a counterpart to "vernal".

Jackie is right. Autumnal is the direct analog of vernal in this instance. However, Wicca gives the autumnal equinox its very own name: Mabon. Mabon's opposite is Ostara. The summer solstice is simply Midsummer. The winter solstice is, familiarly, and somewhat shockingly, Yule.

Interesting that common names for the biggest Christian holidays, Easter and Christmas, are tied to distinctly non-Christian tradition, Ostara (Easter) and Yule. Many of the holiday traditions also are tied to the Pagan practices surrounding Ostara and Yule.

So why not press Mabon or mabontide into service, if you are looking for a more poetic way to refer to the autumnal equinox?