The decibel is a measure of the intensity (loudness) of sound. It is named for Alexander Graham Bell. Decibel is abbreviated dB. Humans with intact hearing systems can typically detect sounds between 0 and 140 (the point at which sound starts to hurt and becomes more “feeling” than “hearing”) decibels.
Audiologists measure hearing thresholds in decibels (loudness) across many frequencies (pitches). Click HERE to learn more about how to read an audiogram.
There are many free apps that enable you to have a decibel meter on your smartphone. It’s a great way to get a quick reading of the noise in a room, but keep in mind these apps are uncalibrated and shouldn’t be used to make any final, scientific determinations about sound intensity.