Definition:Milky Way/Linguistic Note

Linguistic Note on Galaxy
The name Milky Way is a translation of the Latin via lactea, from the Greek γαλακτικός κύκλος (galaktikos kýklos), meaning milky circle.

This arises from the fact that the Milky Way itself appears in the sky as a pale band against the dark sky, supposedly looking like a trickle of milk.