/ Dictionary / Index H hydraulic radius: Meaning and Definition of Find definitions for: hydrau'lic ra'dius Pronunciation: [key] the ratio of the cross-sectional area to the perimeter of a pipe, outlet, or the like, through which a fluid is flowing. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. hydraulic press hydraulic ram Related Content Daily Word Quiz: simian Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language