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