|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|
|—vb , cogs, cogging, cogged|
|4.||(tr) metallurgy to roll (cast-steel ingots) to convert them into blooms|
|[C13: of Scandinavian origin; compare Danish kogge, Swedish kugge, Norwegian kug]|
slip a cog
Also, slip a gear or one's gears. Lose one's ability to reason soundly or make correct judgments, as in She must have slipped a cog or she would never have gone out barefoot in December, or What's the matter with him? Has he slipped his gears? These slangy usages allude to a mechanical failure owing to the cog of a gear or a gear failing to mesh. The first dates from about 1930, the variant from the 1960s.