What is the primary counterpart to the Seasonal Black Moon definition?

Answer

The original definition of a Blue Moon (the third of four Full Moons in a season).

The Seasonal Black Moon definition exists as the exact counterpoint to the original definition of a Blue Moon, which is the third Full Moon out of four in a season.

What is the primary counterpart to the Seasonal Black Moon definition?
astronomytimeMooncelestial eventblack moon