What is the primary reason the term 'Black Moon' is not formally used by professional astronomers?

Answer

It lacks a single, unified astronomical definition.

The text states that the term 'Black Moon' is not formal because it is a popular nickname applied to several different, infrequent patterns within the lunar cycle.

What is the primary reason the term 'Black Moon' is not formally used by professional astronomers?
astronomytimeMooncelestial eventblack moon