decibel

noun deci·bel \ ˈde-sə-ˌbel , -bəl \

|Updated on: 19 Jul 2018

Definition of decibel

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

See decibel defined for English-language learners

See decibel defined for kids

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 of decibel from the Web

The team then pumps nitrogen gas into the horns, which assault the article with 150 decibels.

— sarah scoles, WIRED, "Inside the Test Chamber for NASA's Astronaut Vehicle Double," 12 July 2018
Except for the steady grunt of plows in the distance, the world echoed in decibels of silence.

— beck dorey-stein, Philly.com, "Charles Barkley was star-struck before interviewing president Obama. A stenographer from Narberth calmed him down," 2 July 2018
For a person to buy a silencer, which reduces firearm noise by 20 to 35 decibels, the National Firearms Act currently requires fingerprints and photographs, a fee and a background check that can take up to a year.

— dan frosch, WSJ, "Why More Gun Owners Use Silencers," 5 May 2018
The museum also hosts interactive exhibits, including an Attempt Area where one beefy guy with mighty lungs couldn’t even come close to beating the world record of screaming louder than 129 decibels in a far-from-soundproof room.

— rené a. guzman, San Antonio Express-News, "Curious who goes into Ripley’s by Alamo? So were we," 25 June 2018
The human ear can tolerate noise below 85 decibels without damage.

— Milwaukee Journal Sentinel, "Protect your ears: you might not realize what’s hurting them," 19 June 2018
Boeing’s contest also requires that devices run quieter than 87 decibels, as measured by sensors 50 feet away.

— joshua brustein, latimes.com, "Boeing asked for quiet jet packs but got a bunch of air motorcycles," 14 June 2018
Volume must also increase by three decibels with each 6-mph increase in speed.

— clifford atiyeh, Car and Driver, "Make Some Noise! No More Silent EVs and Hybrids, Says NHTSA [UPDATE]," 28 Feb. 2018
In Cuba, environmental noise over 80 decibels is considered unacceptable in the workplace.

— mimi whitefield, miamiherald, "Cuba: Stress may be behind U.S. diplomats health problems | Miami Herald," 8 Feb. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'decibel.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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.

Origin and Etymology of decibel

International Scientific Vocabulary deci- + bel

NEW! Time Traveler

First Known Use: 1928

in the meaning defined at sense 1a

See Words from the same year

DECIBEL Defined for English Language Learners

decibel

noun

Definition of decibel for English Language Learners

: a unit for measuring how loud a sound is

DECIBEL Defined for Kids

decibel

noun deci·bel \ ˈde-sə-ˌbel , -bəl \

Definition of decibel for Students

: a unit for measuring the loudness of sounds

Medical Dictionary

decibel

noun deci·bel \ ˈdes-ə-bəl , -ˌbel \

medical Definition of decibel

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