1. A unit of loudness of sound, equal to the loudness of a 1 kHz tone at 1 decibel above the threshold of hearing.
Usage: technical; acoustics

Examples

• The sound engineer measured the noise level in phons to ensure it met safety standards.
• A whisper is typically around 30 phons, while normal conversation is about 60 phons.
• The phon scale helps audiologists assess hearing sensitivity across different frequencies.