Piston: A hollow round cylindrical plug in the engine cylinder that transmits the force of combustion in the combustion chamber to the crankshaft via the connecting rod. Related posts: Personnel Management Operative Functions Administrative Role of PM Competency HR Management Role Change Personnel Policies Personnel Procedures Appealed Policies Implied Policies Specific Policies Personnel records Research Pure research Personnel research Attitude or Opinion Survey Turnover Secondary research Applied research Personnel audit Read more articles Previous PostPilot injection Next PostPiston displacement