a gear tooth, formerly especially one of hardwood or metal, fitted into a slot in a gearwheel of less durable material.
a cogwheel.
a person who plays a minor part in a large organization, activity, etc..
He's just a small cog in the financial department.
Carpentry. (in a cogged joint) the tongue in one timber, fitting into a corresponding slot in another.
Mining. a cluster of timber supports for a roof.
any of the teeth or projections on the rim of a gearwheel or sprocket
a gearwheel, esp a small one
a person or thing playing a small part in a large organization or process
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. ))
First recorded in 1525–35; origin uncertain
1855–60; special use of cog 1; replacing cock in same sense, special use of cock 1 (in sense of projection); see coak
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.
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Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
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
It is working with U.S. company MP Materials and the Defense Department on rare-earth-metal refining efforts, making Saudi Arabia an important cog in efforts to reduce the West’s dependency on China.
From The Wall Street Journal ● May 13, 2026
Bohm, 29, soon cemented himself as the Phillies’ everyday third baseman, and he has been a consistent cog on a team that has made four consecutive postseason appearances.
From Los Angeles Times ● Mar. 27, 2026
Dipu was a small cog in Bangladesh's garment export machine, working for the past 14 months at the Pioneer Knitwear factory.
From BBC ● Feb. 15, 2026
"You require passage for a hundred Dothraki, all their horses, yourself and this knight, and three dragons?" said the captain of the great cog Ardent Friend before he walked away laughing.
From "A Clash of Kings" by George R.R. Martin
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
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
"Professor McCabe and Rajah will stay here for a day or two, strictly in cog., you know."
From Shorty McCabe by Wilson, F. Vaux (Francis Vaux)
GRAFVITNIR, from the v. grafa, to dig, to delve; cog. with E. grave: and the v. vita, to know; to wit, wist, wot.
From The Elder Eddas of Saemund Sigfusson; and the Younger Eddas of Snorre Sturleson by Saemund Sigfusson
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
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
I tugged the derrick inboard and recaptured the rope; cogged the winch, swung out, dropped hand over hand into the lane, and raced up it with all the terrors of the law at my heels.
From The Adventures of Harry Revel by Quiller-Couch, Arthur Thomas, Sir
A cogged wheel is so mounted that a ray of light passes between two of the teeth and is reflected back from a mirror.
From The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told by Thomson, J. Arthur
There followed the keen, quick rattling of a cogged wheel and a rush of people who seemed insufficiently impressed by the magnitude of the event.
From Ewing\'s Lady by Wilson, Harry Leon
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
I haue matter in my head against you and your cogging companions, Pistoll and Nym.
From The Merry Wives of Windsor The Works of William Shakespeare [Cambridge Edition] [9 vols.] by Glover, John, librarian of Trinity College, Cambridge
Nay, nay, I do beseech you leave your cogging, what they are, they are, they serve me without Spectacles I thank 'em.
From The Scornful Lady by Fletcher, John
Why, Robin Goodfellow is this same cogging, pettifogging, crackropes, calf-skin companion.
From A Select Collection of Old English Plays, Volume 9 by Various
The hammered billets are again slowly heated and receive a second hammering, known as "cogging."
From The Working of Steel Annealing, Heat Treating and Hardening of Carbon and Alloy Steel by Colvin, Fred H. (Fred Herbert)
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
