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.

---

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.

---

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.

---

verb (used with or without object)

cogged, cogging

1. Carpentry. to join with a cog.

cog. ⁴ American  

abbreviation

1. cognate.

---

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

---

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

---

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

---

cog More Idioms  

More idioms and phrases containing cog

• slip a cog

---

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

Some suspect the actors' gushing words about each other may be just another cog in the film's PR machine, especially given Robbie's husband, Tom Ackerley, is one of its producers.

From BBC • Feb. 13, 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

The underground wealth beneath the Arctic city of Kiruna fuels Sweden’s economy and is a central cog in one of Europe’s core defense industries.

From The Wall Street Journal • Oct. 25, 2025

To his right a war galley stroked serene against the rising sun; to his left, a battered old cog raced before a storm, her sails in rags.

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

Related Words

• prong