loudnessEtymologyFrom Middle English loudnesse, lowdenesse, from Old English hlūdnes, equivalent to loud + -ness.loudness means strength of sound: how loud it is.; The perceptual strength or amplitude of sound pressure, measured in sones or phons. Lexicurio rates it Distinctive — a strength score of 66 out of 100.nounStrength of sound: how loud it is.; The perceptual strength or amplitude of sound pressure, measured in sones or phons.Strength of sound: how loud it is.; The physical strength of the sound pressure level, measured in decibels.