D defs.my
Entry 1 sense Webster, 1913

Apastron

· Ap·as·tron · IPA /æˈpæstɹən/
01 n. That point in the orbit of a double star where the smaller star is farthest from its primary.
  1. 1.
    That point in the orbit of a double star where the smaller star is farthest from its primary.(Astron.)