Meaning of COG in English

COG

[noun] [C] - one of the tooth-like parts around the edge of a wheel in a machine which fits between those of a similar wheel, causing both wheels to moveA cog (also cogwheel) is also a wheel with tooth-like parts around its edge which is used to turn another wheel or part in a machine.(disapproving) If someone is described as a cog in a/the machine, they are a member of a large organization and their job, although necessary, makes them feel unimportant and powerless.I decided to set up my own business because I was tired of just being a cog in a machine.

Cambridge English vocab.      Кембриджский английский словарь.