Meta terminology

U16 / U18

Under-16 / Under-18

Age cohorts below 16 and below 18, used the way U13 is. Excerpt #671 lists "U13 (under 13) children" and "U18 (under 18) teens" as sensitive research populations; excerpt #130 weighs "some level of default (ie., U16 v U18)"; excerpt #628 cites Utah legislation prohibiting U18 late-night social media use without parental consent.