Loudness

noun

1. The state or quality of being loud; great sound or noise; clamor; uproar: as, the loudness of a voice or an instrument.
2. Conspicuousness; flashiness; showiness: as, loudness of dress.
3. The quality or state of being loud.
4. the perceptual strength or amplitude of sound pressure, measured in sones or phons
5. the physical strength of the sound pressure level, measured in decibels