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• cog
  cog

  noun

  a gear tooth, formerly especially one of hardwood or metal, fitted into a slot in a gearwheel of less durable material.
• cog.
  cog.

  abbreviation

  cognate.

cog

¹ American  

[kog, kawg] / kɒg, kɔg /

noun

1. a gear tooth, formerly especially one of hardwood or metal, fitted into a slot in a gearwheel of less durable material.

2. a cogwheel.

3. a person who plays a minor part in a large organization, activity, etc..

   He's just a small cog in the financial department.

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verb (used without object)

cogged, cogging

1. (of an electric motor) to move jerkily.

verb (used with object)

cogged, cogging

1. to roll or hammer (an ingot) into a bloom or slab.

idioms

1. slip a cog, to make a blunder; err.

   One of the clerks must have slipped a cog.

cog ² American  

[kog, kawg] / kɒg, kɔg /

verb (used with object)

cogged, cogging

1. to manipulate or load (dice) unfairly.

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verb (used without object)

cogged, cogging

1. to cheat, especially at dice.

cog ³ American  

[kog, kawg] / kɒg, kɔg /

noun

1. Carpentry. (in a cogged joint) the tongue in one timber, fitting into a corresponding slot in another.

2. Mining. a cluster of timber supports for a roof.

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verb (used with or without object)

cogged, cogging

1. Carpentry. to join with a cog.

cog. ⁴ American  

abbreviation

1. cognate.

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cog ¹ British  

/ kɒɡ /

noun

1. any of the teeth or projections on the rim of a gearwheel or sprocket

2. a gearwheel, esp a small one

3. a person or thing playing a small part in a large organization or process

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verb

1. (tr) metallurgy to roll (cast-steel ingots) to convert them into blooms

cog ² British  

/ kɒɡ /

noun

1. a tenon that projects from the end of a timber beam for fitting into a mortise

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verb

1. (tr) to join (pieces of wood) with cogs

cog ³ British  

/ kɒɡ /

verb

1. slang to cheat (in a game, esp dice), as by loading a dice

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cog More Idioms  

More idioms and phrases containing cog

• slip a cog

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Etymology

Origin of cog¹

First recorded in 1200–50; Middle English cogge, probably from a North Germanic language; compare Swedish kugge, Norwegian kugg “cog”; akin to German Kugel “bullet, ball, shot,” Old English cycgel ( see cudgel ( def. ))

Origin of cog²

First recorded in 1525–35; origin uncertain

Origin of cog³

1855–60; special use of cog ¹; replacing cock in same sense, special use of cock ¹ (in sense of projection); see coak

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Explanation

An engine needs each of its parts to work. It has gears which have wheels. Each wheel has cogs, or tiny teeth that fit together, making the wheel turn, the engine run. Every cog is essential to that engine. People can also be cogs — they are the workers who, day in and day out, perform their duties seemingly with no end in sight. Feeling disheartened, they might say, "I'm just a cog in the system." If you hear this, remind them of the true definition of the term cog — an instrumental part of the whole.

Example Sentences

See Examples For:

cog cog. cogged cogging

And for these Dodgers — whose fourth starter, Tyler Glasnow, was a key cog in last year’s World Series-winning rotation — it’s a fair assessment.

From Los Angeles Times ● Oct. 4, 2026

The following season, Ramsdale was a vital cog in Arsenal's spine as they launched a surprise title challenge, only to be outdone by an imperious Manchester City side.

From BBC ● Sep. 28, 2026

When mediocrity is the core objective of an extremely powerful company like this one, success hinges on turning the once-discerning viewer into a machine cog as mindless as one of Netflix’s baffling originals.

From Salon ● Sep. 2, 2026

The enormous cash injection comes as Asia's fourth-largest economy rides high on a global AI boom -- with South Korean memory chipmakers emerging as a crucial cog in the fast-moving industry.

From Barron's ● Jun. 29, 2026

Tyrion had learned to despise that man, even if he was the only half-decent cyvasse player on the cog.

From "A Dance with Dragons" by George R. R. Martin

L. anderius, andena; further ety. dubious, perhaps ultimately cog. with End.

From Chambers's Twentieth Century Dictionary (part 1 of 4: A-D) by Various

O. Fr. flosche, down: or from some Teut. word cog. with fleece—cf.

From Chambers's Twentieth Century Dictionary (part 2 of 4: E-M) by Various

"Professor McCabe and Rajah will stay here for a day or two, strictly in cog., you know."

From Shorty McCabe by F. Vaux (Francis Vaux) Wilson

VASADR, from vas, moisture, a word cog. with the E. wet and wash.

From The Elder Eddas of Saemund Sigfusson; and the Younger Eddas of Snorre Sturleson by Saemund Sigfusson

BRAGI, the name of the God of Poetry; from braga, to glisten, to shine, or from bragga, to adorn; ph. cog. with G. pracht, splendour.

From The Elder Eddas of Saemund Sigfusson; and the Younger Eddas of Snorre Sturleson by Saemund Sigfusson

The battery operated Space Express has cogged wheels and can travel vertically up or upside down on a cogged track.

From Nature ● Dec. 17, 2018

And then there's the marvellous Druzhba sanatorium by the sea at Yalta, a stack of cogged carousels rising out of a bank of trees, each notch a living space.

From The Guardian ● Feb. 7, 2011

The instrument is then set vertical, by a spirit-level on the cogged driving-wheel, and the four pairs of set screws on the clamp-head embracing the cascabel.

From Ordnance Instructions for the United States Navy. 1866. Fourth edition. by United States. Navy Dept. Bureau of Ordnance

Butter is made in one of their pots with a churning-stick, consisting of a cogged wheel fixed on to the end of a wooden rod.

From The Tribes and Castes of the Central Provinces of India Volume II by R. V. (Robert Vane) Russell

A cogged joint is stronger than a notched because the upper beam is not weakened at its point of support.

From Handwork in Wood by William Noyes

A new coreless direct drive motor should eliminate the minor cogging issue some SL-1200 turntables experienced — tiny vibrations that can cause rotation irregularities.

From The Verge ● Jan. 7, 2019

Why, Robin Goodfellow is this same cogging, pettifogging, crackropes, calf-skin companion.

From A Select Collection of Old English Plays, Volume 9 by Various

Such a system of cogging, such a system of fraud, such a system of prevarication, such a system of falsehood, never was, I believe, before exhibited in the world.

From The Works of the Right Honourable Edmund Burke, Vol. 10 (of 12) by Edmund Burke

Thy eyes are shut, thy tongue cannot be cogging; Nothing of profit rests at thy dispose.

From The Complete Works of Richard Crashaw, Volume II (of 2) by Richard Crashaw

In pride, deceit, prating, lying, cogging, coyness, spite, hate, sir.

From A Select Collection of Old English Plays, Volume 9 by Various

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