In mechanics, a journal is the section of a rotating shaft (such as an axle, driveshaft, or spindle) that contacts and turns in a bearing. In automotive engineering, the term journal specifically describes the connection between the crankshaft and the main bearings (as opposed to the connection between the crankshaft and the connecting rod bearings). Mechanics refers to: a craft relating to machinery (from the Latin mechanicus, from the Greek mechanikos, meaning one skilled in machines), or a range of disciplines in science and engineering. ... An axle is a central shaft for a rotating wheel or gear. ... Cardan driveshaft with universal joints A driveshaft or driving shaft or Cardan shaft is a mechanical device for transferring power from the engine or motor to the point where useful work is applied. ... The word spindle might (or might not) have several meanings: A spindle (shrub), a poisonous shrub or small tree of the genus Euonymus. ... A bearing is a component used to reduce friction in a machine. ... Engineering is the application of science to the needs of humanity. ... Crankshaft Continental engine marine crankshafts, 1942 Crankshaft is also the name of a comic strip about an old, curmudgeonly bus driver. ... piston + connecting rod In a reciprocating piston engine, the connecting rod or con rod connects the piston to the crank or crankshaft. ...