The term 'tooth wheel' is a collective name for three different components of a mechanical system: a GEAR, a SPROCKET, and a COG. A GEAR is a toothed wheel that meshes with another toothed wheel or a linear toothed part, allowing rotational force to be transferred from one part to another. A SPROCKET is a toothed wheel with teeth that mesh with a chain, allowing the chain to move and transfer power. A COG is a toothed wheel that meshes with another toothed wheel, allowing rotational force to be transferred from one part to another. Together, these three components form the tooth wheel, which is used to transfer power in a mechanical system.