/ Dictionary / Index G galactic year: Meaning and Definition of Find definitions for: galac'tic year' Pronunciation: [key] — Astron. Astron. the duration of a complete rotation of the Milky Way, approximately 200 million years. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. galactic pole galactin Related Content Daily Word Quiz: reticent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language