Transmission 1 : (n) The gear or chain arrangement by which power is transmitted from the prime mover to the drawworks, the mud pump, or the rotary table of a drilling rig
US Department of Labor, Occupational Safety & Health Administration (OSHA), Oil and Gas Well Drilling and Servicing eTool, Washington, DC. This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin, USA 2001. http://www.osha.gov/SLTC/etools/oilandgas/glossary _of_terms/glossary_of_terms_a.html, (Oil Well Drilling Sci and Tech - Amer) {492}