cog
n. countablen. a wheel with teeth around the edge that fits into another wheel to make a machine move. It is also used to describe a person who does a small but necessary job in a large organization.
n. a tooth on the rim of a wheel or gear that transfers motion by engaging with another toothed part; by extension, a person who performs a minor but essential role within a large system.
The machine stopped working because a single cog was broken.
He felt like a small cog in a giant corporate machine, where his individual efforts were rarely noticed by the directors.
The clockmaker carefully filed each individual cog to ensure the gears would mesh perfectly without any friction or noise.
Inherited from Middle English cogge, from Old Norse kogge, koggr (see Old Swedish kogge, kogger), from Proto-Germanic kuggō (“cog, swelling”), from Proto-Indo-European gugā (“hump, ball”), from *gēw- (“to bend, arch”). Compare Lithuanian gugà (“pommel, hump, hill”). Cognates includes: Swedish kugg, kugge (“cog tooth”), Norwegian kugg (“cog”). The meaning of “cog” in carpentry derives from association with a tooth on a cogwheel. Compare Old Swedish koggavidher (“cog wood”), “wood reserved for a millwheel”. See also dialectal English cag (“stump”), keg; Old Norse kaggi (“keg”) + -gi (diminutive suffix), from the Germanic base *kagô (“bush, branch, stalk, stump”); also found in Bavarian Kag (“the stalk or stem of a cabbage”); dialectal Swedish kage (“treestump; piece of wood; post”), kagg or kagge (“scythe handle”); Norwegian Nynorsk kage or kagge (“low lying bush, small tree”), dialectal kagg (“scythe handle”); Old English ċeacga (“broom, furze, gorse”), whence English chag (“branch”), also Old English cyċġel, English cudgel (“knotty club”). The ultimate origin could be related to English cog (“cargo boat”) (Dutch kogge), probably named for its “round swollen” appearance.
From Middle English cogge, from Middle Dutch kogge, cogghe (modern kogge), from Proto-Germanic kuggō, from Proto-Indo-European gugā (“hump, ball”) (compare Lithuanian gugà (“pommel, hump, hill”)), from *gēw- (“to bend, arch”). See etymology 1 above.
Uncertain. Both verb and noun appear first in 1532.
Often used in the metaphorical idiom 'a cog in the machine' to describe a person's role in a hierarchy.