Are there clear definitions? And are these definitions updated to reflect current times? For example, some younger folks today might have high incomes, but cou

Are there clear definitions? And are these definitions updated to reflect current times? For example, some younger folks today might have high incomes, but could never buy a home due to asset prices and have most of that go towards rent and student debt. Compare against our parents generation and even low income families have a decent chance of owning a home and I'd guess lower levels of student debt. So that said... What does it mean to be middle class in this day and age when income alone may not paint a clear picture?