/ Dictionary / Index H Hillsborough: Meaning and Definition of Find definitions for: Hills•bor•ough Pronunciation: (hilz'bûr"ō, -bur"ō), [key] — n. a town in W California. 10,451. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Hillsboro Hillsdale Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language