/ Dictionary / Index H Hubble's constant: Meaning and Definition of Find definitions for: Hub'ble's con'stant Pronunciation: [key] — Astron. Astron. the ratio of the recessional velocity of galaxies to their distance from the sun, with current measurements of its value ranging from 50 to 100 km/sec per megaparsec. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. hubble-bubble Hubble's law Related Content Daily Word Quiz: soporific Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language