trivium
The lower division of the liberal arts in a medieval university; grammar, logic, and rhetoric.
historical
Surely some demon must possess the lad, / Who showed more wit than ever school-boy had, / And learned his Trivium thus without the rod; / But Alcuin said it was the grace of God.
The three anterior ambulacra of echinoderms, collectively.
Where it comes from
Borrowed from Latin trivium.
Adapted from the Wiktionary entry trivium (CC BY-SA 4.0).