Cog is a type of gear or wheel with teeth that interlock with other gears to transmit motion and force in machines. It plays a crucial role in mechanical systems, allowing for the conversion of rotational motion into linear motion or vice versa. Cogs are commonly found in various devices, from simple clocks to complex machinery. In addition to its mechanical function, the term "cog" can also refer to a small, often cylindrical part of a larger system. In the context of engineering and mechanics, understanding how cogs work is essential for designing efficient machines and ensuring they operate smoothly.