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 ( 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); coak

Example Sentences

Among the targets in recent days was the IRGC’s Tharallah headquarters on Sunday, a central cog in the forces’ protest-suppression machine.

From The Wall Street Journal • Mar. 4, 2026

“I do think Google’s self-sufficiency should command a premium relative to the others that could be adversely impacted by one cog in the wheel,” Treacy said, referring to Google’s proprietary tensor processing units.

From MarketWatch • Feb. 12, 2026

But he figures to be a key cog in their bullpen again next season, in what will be his last before reaching free agency.

From Los Angeles Times • Nov. 6, 2025

Fishlock wasted no time in becoming a key cog under Andy Beattie, Adrian Tucker, Jarmo Matikainen, Jayne Ludlow, Gemma Grainger and most recently Wilkinson.

From BBC • Oct. 15, 2025

The big cog stayed well out from them, tacking.

From "A Clash of Kings" by George R.R. Martin

Related Words

• prong