Correct me if I’m wrong, as I’m sort of learning this stuff, but it’s a solemnity (like today) which supersedes a penitential day, which is a feast of the highest magnitude. But the many other feast days throughout the year that are not solemnities, well, no dice.
Further, can someone clarify: all holy days of obligation are solemnities, but not all solemnities are holy days of obligation? Yes or no?