These terms derive from burgeoning online communities in which adult children estranged from their parents gather in groups for mutual support. This kind of alienation isn’t new; it probably goes back as far as the family unit itself. What’s unique to the era of gen Z and millennial kids cutting their gen X and boomer parents out of their lives is codification, an attempt to legitimise and name a traumatic experience in an effort to remove stigma and guilt from painful decisions.