Young adults (a generational unit) considered as a cultural class or subculture(noun)
WordNet. Princeton University. 2010.
Use "youth culture" in a sentence
"“Pepsi has always stood for youthful exuberance and optimism and we’re pleased to learn through this survey that the positive spirit in youth culture is not only intact but growing,” said Dave Burwick, Pepsi’s chief marketing officer."
"With the West no longer completely cut off, Czech youth immediately tapped into the vibrant Western youth culture wearing Texasskis — blue jeans — and going to clubs to hear the big beat, as rock and roll was called."