galact(o)-

Milk; galactose.

Greek gala, galakt‑, milk.

The sugar galactose derives from milk. The form sometimes marks its presence in a chemical compound, for example galactoside, a glycoside, and galactan, which occurs in seaweeds and some other plants. In medicine, a galactagogue (Greek agōgos, eliciting) is a food or drug that induces the flow of a mother's milk. The adjective galactic can refer to milk, but more commonly alludes to galaxies, originally the band of stars across the heavens called the Milky Way.