"retro core" means: Retro core is a deliberately curated aesthetic that goes all-in on throwback visual culture — drawing from VHS grain, 80s neon, 90s grunge.... This is a fairly neutral word with no inherent risk attached. There is no real cause for parental concern; it is descriptive vocabulary rather than something dangerous. If your child uses it, context will usually make the meaning clear. A brief, curious question about where they heard it is generally enough to know whether to follow up.