Transmission wheel (US: crown-wheel)

Usually an object of circular shape with contrate teeth, which meshes with the winding pinion and with the ratchet-wheel on the barrel-arbor used to wind-up the watch, respectively to set the time.

Source: G.A. Berner 4-language Glossary, 1988 re-edition, courtesy FH, Federation of the Swiss Watch Industry, Bienne, Switzerland

External Berner Glossary Source:

• FH: Glossary