Etymon
lat-tri-protoindoeuropean-weyh1-protoitalic-wija-latin-via-protoindoeuropean-yos-protoitalic-ios-old-latin-ios-latin-ius-latin-trivius-latin-trivia-english-trivia-from-latin-trivia
A dedicated page for this root is on the way — it will gather every word descended from it, sibling forms across daughter languages, and a branching map of the family tree.