means Resembling milk — pale, cloudy, or opaque white, often with a soft, hazy quality.

from From Old English 'milc' (milk), the same root that runs through German 'Milch' and ultimately back to a Proto-Indo-European root meaning 'to wipe' or 'to stroke' — likely a nod to the milking motion itself. The '-y' suffix simply means 'having the quality of,' so 'milky' has always meant, quite literally, 'milk-like.' The astronomical sense comes via the Milky Way, an English calque of Latin 'via lactea,' itself translating the Greek 'galaxias kyklos' — the 'milky circle' — for that pale band of light smeared across the night sky.