decibel

American  

[des-uh-bel, -buhl] / ˈdɛs əˌbɛl, -bəl /

noun

Physics.

• decibels
  plural

1. a unit used to express the intensity of a sound wave, equal to 20 times the common logarithm of the ratio of the pressure produced by the sound wave to a reference pressure, usually 0.0002 microbar.

2. a unit of power ratio, the number of units being equal to a constant times the logarithm to the base 10 of the intensities of two sources.

3. a unit used to compare two voltages or currents, equal to 20 times the common logarithm of the ratio of the voltages or currents measured across equal resistances. dB, db

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decibel British  

/ ˈdɛsɪˌbɛl /

noun

1. a unit for comparing two currents, voltages, or power levels, equal to one tenth of a bel

2. a similar unit for measuring the intensity of a sound. It is equal to ten times the logarithm to the base ten of the ratio of the intensity of the sound to be measured to the intensity of some reference sound, usually the lowest audible note of the same frequency

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decibel Scientific  

/ dĕs′ə-bəl /

1. A unit used to measure the power of a signal, such as an electrical signal or sound, relative to some reference level. An increase of ten decibels in the power of a signal is equivalent to increasing its power by a factor of ten. As a measure of sound intensity, a zero-decibel reference is stipulated to be the lowest level audible to the human ear; the speaking voice of most people ranges from 45 to 75 decibels.

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decibel Cultural  

1. A unit of measurement of the volume of sounds.

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Other Word Forms

Noun Inflected Forms

• decibels
  plural

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Etymology

Origin of decibel

First recorded in 1925–30; deci- + bel ¹

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Explanation

A decibel is a unit of measurement that tells you exactly how loud a sound is. While a whisper is about 15 decibels, your neighbor's chain saw is about 120 decibels. Better invest in some ear plugs! Because our ears are so incredibly sensitive to noise, the decibel scale has an enormous range. The 120 decibel sound of an airplane's jet engine is actually one trillion times louder than the very quietest sound your ear can hear. The word decibel, coined in 1928 by engineers in the telephone industry, originally measured the efficiency of a telephone circuit.

Example Sentences

See Examples For:

decibel decibels

The decibel levels were rarely matched in an underwhelming first set for the home favourites, but the noise quickly returned when they rallied in the second set.

From BBC ● Sep. 5, 2026

In February, it approved an ordinance for data centers with requirements that included decibel limits and buffer zones from certain properties.

From The Wall Street Journal ● Aug. 16, 2026

If the maximum decibel level was a 10, this one went up to 11.

From BBC ● May 4, 2026

And like all of television, reality is facing splintered and waning audiences so the decibel level of that conversation-sparking is often dialed way up.

From Los Angeles Times ● Mar. 21, 2026

To Ben, his father’s voice was the most fearsome he had ever heard, could inspire the most panic per decibel.

From "The Great Santini" by Pat Conroy

The company said its backup diesel generators run only for five minute tests each week and, thanks to abatement efforts, produce "about 44 decibels of sound, quieter than a soft conversation three feet away."

From Barron's ● Oct. 26, 2026

Spectators are advised to wear ear defenders - the noise is comparable in decibels to standing next to a fighter jet taking off.

From BBC ● Oct. 8, 2026

Judging by the decibels of applause, everyone—from the cast and crew to the Ramp workforce to the “influencers group” to the rest of the attendees—seemed to agree.

From Slate ● Oct. 1, 2026

The Rumbler interacts with a standard police siren, which generates around 110 to 120 decibels, and amplifies that sound through its speakers in eight-second intervals.

From Los Angeles Times ● Aug. 10, 2026

Scientists measure the amplitude of sound waves in decibels.

From "Understanding Basic Music Theory" by Catherine Schmidt-Jones and Russel Jones

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