I'm trying to go deeper into my study of chromatic harmony.
I was reading through the Tonal Harmony textbook, and it says that a "simultaneity" is "a chord for which a traditional Roman numeral label would be of secondary importance." The glossary says "the use of a traditional Roman numeral label is meaningless for such chords because the resulting tones do not function in the traditional sense."
When these chords come up in the book, they simply write out the actual letter for the chord instead of a Roman numeral.
However, when I looked up this term online, I didn't see anything come up related to the definition they provided.
Have any of you encountered different terminology for chords that are better explained without the use of Roman numerals? I don't know if other texts refer to this concept in a different way once they get to areas of deeper chromatic harmony.
Let me know any thoughts or knowledge you have about this; I'd appreciate it. Thanks in advance!