The cog is one of civilization's oldest technologies — the 2,100-year-old Antikythera mechanism used bronze cogs to compute planetary positions, and the word became a metaphor for human insignificance in machines.
A tooth or projection on a gear wheel that meshes with another gear to transmit motion. Also used figuratively to describe a person who plays a small but necessary role in a larger organization.
From Middle English cogge (cog, tooth of a wheel), probably from Scandinavian, related to Swedish kugge (cog, tooth), Norwegian kugg (cog), of uncertain deeper origin, possibly onomatopoeic or from a root meaning 'rounded projection' Key roots: kugge (Old Swedish: "cog, tooth").
The phrase "a cog in the machine" — meaning a small, replaceable part of a large system — is one of English's most powerful metaphors for industrial alienation. Charlie Chaplin's Modern Times (1936) literally depicted the worker as a cog, with Chaplin's character getting pulled through the gears of a factory machine. The metaphor predates industrialization: the earliest known geared mechanism is the Antikythera mechanism (c. 100 BCE), an ancient Greek astronomical computer recovered from a Mediterranean shipwreck, whose bronze cog wheels computed