perihelion/ˌperɪˈhi:lɪən; ˌpɛrɪ`hilɪən/ n(pl -lia / -lɪə;-lɪə/) point in the orbit of a planet, comet, etc at which it is nearest to the sun 近日点（行星、 彗星等轨道上距太阳最近的点）.
牛津英汉双解词典