银道圈

Galactic \Ga*lac"tic\, a. [Gr. ? milky, fr. ?, ?, milk. See
{Galaxy}, and cf. {Lactic}.]
1. Of or pertaining to milk; got from milk; as, galactic
acid.

2. Of or pertaining to the galaxy or Milky Way.

{Galactic circle} (Astron.), the great circle of the heavens,
to which the course of the galaxy most nearly conforms.
--Herschel.

{Galactic poles}, the poles of the galactic circle.