[ ee-kwuh-lahy-zer ]
/ ˈi kwəˌlaɪ zər /
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a person or thing that equalizes.
any of various devices or appliances for equalizing strains, pressures, etc.
Electricity. an electric network of inductance, capacitance, or resistance established between two points in a given network to secure some constant relation, as even attenuation, between the two points.
Slang. a weapon, as a pistol, blackjack, or switchblade knife.
Should you take this quiz on “shall” versus “should”? It should prove to be a quick challenge!
Question 1 of 6
Which form is used to state an obligation or duty someone has?

Origin of equalizer

First recorded in 1785–95; equalize + -er1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022


What else does equalizer mean?

An equalizer levels the playing field or otherwise evens discrepancies out. The term can variously refer to: weapons, score-tying points in sports, a device that modifies sound frequencies, and forces or phenomena that balance out social inequalities.

What are some other forms of equalizer?

(chiefly British) equaliser

Where does equalizer come from?

Equalizer is literally “something that equalizes,” with equalize meaning “to make equal.” The word equalizer is first recorded in the late 1700s. Early instances of the word especially referred to various devices that could make speed, temperature, pressure, or the like uniform.

Horace Mann, the influential American educational reformer and Whig politician, used the word equalizer as a mechanical metaphor in 1848 when he intoned his famous words: “Education, then, beyond all other devices of human origin, is the great equalizer of the conditions of men—the balance-wheel of the social machinery.” For Mann, education, ideally, enables everyone to have an equal shot at economic and social success.

The “weapons” sense of equalizers emerged by the late 1890s, first used for a knife or bomb and later and more commonly by the 1920s, a gun. This equalizer is cruelly ironic, as a weapon makes all fates equal to those before it. In contemporary use, the term has taken on a more literal use when gun-rights advocates speak of their weapons as equalizers during an attack (i.e., they give a weaker person more of a chance against a foe).

Technological developments in the late 1920s gave us another sense of the word with the invention of the equalizer, a device designed to help balance out frequencies of sound by dropping or boosting the bass, mid, and treble. Know that thingy in your car stereo that allows you to play with the sound levels? That’s essentially an equalizer, though music producers and editors use ones with lots more knobs. Music producers refer to the act of equalization as EQ for short.

In sports, points that bring a score to a tie were being called equalizers by the 1930s, originally (and still) in soccer. The term gradually spread to other sports and can now be used in the coverage of any kind of point-based game.

And who is The Equalizer? In pop culture, The Equalizer refers to a 1980s TV series (adapted into films in 2014 and 2018 starring Denzel Washington) featuring a vigilante who calls himself the Equalizer, serving justice for those who aren’t strong enough to do it themselves—with his wits and weapons. Yes, there are several senses of equalizer at work here.

How is equalizer used in real life?

Using and understanding equalizer is all about context, given the many senses of the word.

Musicians and music producers may use an equalizer when recording and editing audio. Sports journalists may use equalizer when calling a tying point in a game.


Evoking the famous phrase of Horace Mann, the phrase great equalizer is specifically used to refer to various forces or phenomena that give everyone in an unequal position a fair shot—or, more tragically, reduce all people to the same circumstances.

In 2020, COVID-19 was sometimes originally discussed as the great equalizer in that it forced rich and poor, young and old, black and white, to stay at home and infected all types of people regardless of their background. However, many people criticized use of this phrase due to evidence COVID-19 disproportionately infected people of color, for instance, or that wealthier communities had more access to high-quality education, medical testing and supplies, and the internet during shelter-in-place orders.


While calling, say, a shotgun an equalizer sounds old-fashioned today, some gun owners and gun-rights activists do refer to guns as equalizers for women facing male assailants.

More examples of equalizer:

“Is Digital the Great Equalizer When It Comes to Gender Equality at Work?”

—Ellyn Shook, HuffPost (headline), March 2016

“Shortly after falling behind on a second-half goal by Burnley’s Matej Vydra, Bournemouth thought they had scored a well-worked equalizer.”

—Doug McIntyre, Yahoo Sports, February 2020

How to use equalizer in a sentence

British Dictionary definitions for equalizer



/ (ˈiːkwəˌlaɪzə) /

a person or thing that equalizes, esp a device to counterbalance opposing forces
an electronic network introduced into a transmission circuit to alter its response, esp to reduce distortion by equalizing its response over a specified frequency range
sport a goal, point, etc, that levels the score
US slang a weapon, esp a gun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for equalizer

[ ēkwə-lī′zər ]

An electronic device made of filters and amplifiers, used to alter the relative strengths of different frequencies in an electronic signal. Equalizers are used primarily in audio equipment, allowing fine-tuning of the signal to compensate for distortions such as weak response or oversensitivity at various frequencies.♦ A graphic equalizer uses a set of controls that determine the level of boost or suppression of individual frequencies. The controls are usually sliding faders, set up in a row from lowest frequency to highest frequency, so that the final settings resemble a graph of the frequency response of the equalizer.♦ A parametric equalizer consists of one or more filters whose characteristics can be controlled, such as the frequency to be manipulated, whether to boost or suppress the frequency, the amount of boost or suppression, and how much nearby frequencies are also affected.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.