Resurgence means coming back. Biker jackets are always cool––but in certain decades they experience a resurgence, and suddenly you see them everywhere.
There is nothing steady about resurgence––a surge is a sudden gush––think dancing fountain or an oil well that's just been tapped. Often, after a national tragedy, there is a resurgence in interest in family values and getting back to basics. In prosperous times, there's often a resurgence in sales of contemporary art.