noun
11.1an ancient triangular lyre or harp
古三角琴。
1.2a triangular cutting region formed by three cusps on an upper molar tooth
（上磨牙的）咬嚼区。
词源
early 17th cent. （in the sense 'triangle'）： via Latin from Greek trigōnon, neuter of trigōnos 'three-cornered'.