/ Dictionary / Index R relative humidity: Meaning and Definition of Find definitions for: rel'ative humid'ity Pronunciation: [key] the amount of water vapor in the air, expressed as a percentage of the maximum amount that the air could hold at the given temperature; the ratio of the actual water vapor pressure to the saturation vapor pressure. Abbr.: RH, rh &hasp;Also calledCf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. relative frequency relative impediment Related Content Daily Word Quiz: kiln Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language