12 letters · 18 points in Scrabble
noun the mathematics of triangles and trigonometric functions
originPIE word *tréyes From 1610s, from New Latin trigōnometria, from Ancient Greek τρίγωνον (trígōnon, “triangle”) + μέτρον (métron, “measure”), equivalent to trigono- + -metry.
Etymology from Wiktionary, CC BY-SA 3.0