decibel

noun

deci·​bel ˈde-sə-ˌbel  -bəl 

1

a

: a unit for expressing the ratio of two amounts of electric or acoustic signal power equal to 10 times the common logarithm of this ratio

b

: a unit for expressing the ratio of the magnitudes of two electric voltages or currents or analogous acoustic quantities equal to 20 times the common logarithm of the voltage or current ratio

2

: a unit for expressing the relative intensity of sounds on a scale from zero for the average least perceptible sound to about 130 for the average pain level

3

: degree of loudness

also : extremely loud sound

—usually used in plural

Did you know?

The unit for measuring the relative intensities of sound is called a decibel. Because the decibel scale is logarithmic, a sound with an intensity that is twice that of a reference sound corresponds to an increase of little more than 3 decibels. In common practice, the reference point of 0 decibel is set at the intensity of the least perceptible sound, the threshold of hearing. On such a scale a 10-decibel sound is 10 times the intensity of the reference sound; a 20-decibel sound is 100 times the reference intensity, and so on. Normal conversation is usually around 60 decibels, an electric saw around 100 decibels, and amplified rock music around 120 decibels.

Synonyms

• babel
• blare
• bluster
• bowwow
• brawl
• bruit [archaic]
• cacophony
• chatter
• clamor
• clangor
• din
• discordance
• katzenjammer
• noise
• racket
• rattle
• roar

Examples of decibel in a Sentence

a rock concert blasting music at 110 decibels

the crowd decibels increased dramatically as the horses neared the finish line

Recent Examples on the Web

That’s dramatically quieter than the 75 decibels that retailer Tractor Supply Co. estimates as the volume of an average push mower. —Tyler Hayes, PC Magazine, 10 May 2025

Conversely, if a Black person was so much as suspected of a crime, the Post could turn its citywide volume up to a perilous decibel, with sometimes terrible consequences. —Vinson Cunningham, New Yorker, 5 May 2025

The home crowd found extra decibels for clears by Dylan DeMelo and Neal Pionk, while Schenn came out of the box just in time for a breakaway pass from Morrissey. —Jeremy Rutherford, New York Times, 22 Apr. 2025

The Who made the Guinness Book of World Records on May 31, 1976, when the sound at the band’s performance at The Valley stadium in Charlton, London, hit 126 decibels, Ultimate Classic Rock reported. —Tim Lammers, Forbes.com, 30 Mar. 2025

Word History

Etymology

International Scientific Vocabulary deci- + bel

First Known Use

1928, in the meaning defined at sense 1a

Rhymes for decibel

• bagatelle
• caravel
• carousel
• carrousel
• citadel
• clientele
• commonweal
• demoiselle
• fontanelle
• infidel
• isabel
• machiavel

Kids Definition

decibel

noun

deci·​bel ˈdes-ə-ˌbel 

-bəl

: a unit for measuring the relative loudness of sounds

—abbreviation dB

Medical Definition

decibel

noun

deci·​bel ˈdes-ə-bəl  -ˌbel 

1

a

: a unit for expressing the ratio of two amounts of electric or acoustic signal power equal to 10 times the common logarithm of this ratio

b

: a unit for expressing the ratio of the magnitudes of two electric voltages or currents or analogous acoustic quantities equal to 20 times the common logarithm of the voltage or current ratio

2

: a unit for expressing the relative intensity of sounds on a scale from zero for the average least perceptible sound to about 130 for the average pain level