Etymon
en-prognosticate-protoindoeuropean-tor-protoitalic-tor-latin-tor-protoindoeuropean-yos-protoitalic-ios-old-latin-ios-latin-ius-latin-toriusder
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.