D defs.my
Entry 1 sense Webster, 1913

Perihelion

/pĕr'ə-hēʼlē-ən/ · Per·i·hel·ion · IPA /ˌpɛɹ.əˈhiː.li.ən/
01 n. That point of the orbit of a planet or comet which is nearest to the sun; -- opposed to aphelion.
pl. Perihelia ((#))
  1. 1.
    That point of the orbit of a planet or comet which is nearest to the sun; -- opposed to aphelion.(Astron.)