Galactic

google

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mid 19th century: from Greek galaktias (variant of galaxias ‘galaxy’) + -ic.

wiktionary

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Borrowed from Ancient Greek γαλακτικός(galaktikós, “milky”), from γάλα(gála, “milk”). Doublet of galactico.

etymonline

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galactic (adj.)

1839, "of the Milky Way, of the bright band of stars around the night sky," from Late Latin galacticus, from galaxias (see galaxy). In modern scientific sense "pertaining to (our) galaxy," from 1849. From 1844 as "of or pertaining to milk."